chore: Add readme to ddp-client package (#31304)

Co-authored-by: Guilherme Gazzo <guilhermegazzo@gmail.com>

.changeset/cyan-balloons-unite.md

+---
+"@rocket.chat/ddp-client": patch
+---
+
+chore: Add readme to ddp-client package

ee/packages/ddp-client/README.md

+# Getting started
+Add `@rocket.chat/ddp-client`  and `@rocket.chat/emitter` as dependencies of your project:
+
+`yarn add @rocket.chat/ddp-client @rocket.chat/emitter`
+or:
+`npm install @rocket.chat/ddp-client @rocket.chat/emitter`
+
+> @rocket.chat/emitter is listed as a peer dependency of ddp-client and is strictly necessary to make it work.
+
+> Tip: The whole project is typed using typescript. For that reason, references to interfaces and objects will be kept to a minimum.
+
+## Setting up the SDK
+ >This works out of the box for browsers. if you want to use it on NodeJS, you need to offer a `WebSocket`  implementation and a `fetch` implementation.
+
+ First things first, let's import the SDK:
+ `import  { DDPSDK }  from  '@rocket.chat/ddp-client';`
+ 
+ Now we need to create a new SDK instance. Fortunately, `DDPSDK` exposes a `create` function that initalizes everything for a quick setup:
+ `const  sdk  =  DDPSDK.create('http://localhost:3000');`
+ 
+ We can then try to connect to the Rocket.Chat instance by doing:
+ `await sdk.connection.connect();`
+ 
+ You can check the connection status by referencing `sdk.connection.status`. If everything went right, it's value should be `'connected'`.
+
+> If you're feeling fancy, you can create and connect in a single function call:
+> `const  sdk  =  DDPSDK.createAndConnect('http://localhost:3000');`
+
+## SDK Modules
+### Connection
+
+Responsible for the connection to the server, status and connection states.
+
+### Account
+
+Responsible for the account management, login, logout, handle credentials, get user information, etc.
+
+### ClientStream
+
+Responsible for the DDP communication, method calls, subscriptions, etc.
+
+### TimeoutControl
+
+Responsible for the Reconnection control
+
+### RestClient
+
+Responsible for the REST API communication for more info [see here](https://developer.rocket.chat/reference/api/rest-api)
+
+## Login handling
+
+The just created `sdk` exposes an `account` interface (`sdk.account`), which should have everything you need. It has 3 methods:
+
+ 1. `sdk.account.loginWithPassword(username, hashedPassword)`
+	 - This method accepts 2 parameters, `username` and `password`. The password must be hashed as `sha-256` for it to work
+ 2. `sdk.account.loginWithToken('userTokenGoesHere')`
+	  - If you already got the token someway through the API, you can call this method.
+ 3. `sdk.account.logout()`
+	  - This one is self-explanatory.
+
+While the `sdk` instance is kept in memory, you can find some user information and credentials by referencing `sdk.account.user`
+
+## REST API
+> TIP: You might have to enable CORS in your Rocket.Chat instance for this to work.
+
+The sdk exposes a `rest` interface, which accept all rest methods (`get`, `post`, `put`, `delete`).
+
+Example call:
+`await sdk.rest.post('/v1/chat.sendMessage',  { message:  { rid: id, msg }  });`
+
+> WARNING: if you wrap a rest call in a try catch block, the error will be of type `Response`. By calling `error.json()` you get access to the server error response.
+
+## Streams
+
+Rocket.Chat uses websockets as to provide realtime data. You can subscribe to publications in order to listen to data updates.
+
+Below is an example of subscribing to the room-messages publication, which receives message updates from a room:
+```ts
+const messages = new Map([]);
+const stream = sdk.stream('room-messages', roomId,  (args)  =>  {
+	setMessages((messages)  =>  {
+	messages.set(args._id, args);
+	return  new  Map(messages);
+});
+
+// Stop the stream when you're done
+stream.stop();
+```
+
+> TIP: always unsubscribe from publications when you're done with them. This saves bandwidth and server resources

ee/packages/ddp-client/src/README.md

-[rest]: https://rocket.chat/docs/developer-guides/rest-api/
-[api-rest]: ../../api-client/
-
-<!-- [start]: https://github.com/RocketChat/Rocket.Chat.js.SDK/blob/master/src/utils/start.ts -->
-
-# Rocket.Chat Javascript/Typescript SDK
-
-Library for building Rocket.Chat clients in Javascript/Typescript.
-
-## Quick Start
-
-```
-npm install @rocket.chat/sdk --save
-```
-
-or
-
-```
-yarn add @rocket.chat/sdk
-```
-
-This is pretty straightforward, but covers all the basics you need to do!
-
-```ts
-import { DDPSDK } from '@rocket.chat/sdk';
-
-const sdk = DDPSDK.create('http://localhost:3000');
-
-await sdk.connection.connect();
-
-await sdk.accounts.login({
-	user: {
-		username: 'username',
-	},
-	password: 'password',
-});
-
-await sdk.stream('room-messages', 'GENERAL', (data) => {
-	console.log('RECEIVED->>', data);
-});
-
-await sdk.rest.post('chat.postMessage', {
-	rid: 'GENERAL',
-	msg: 'Hello World',
-});
-```
-
-This works out of the box for browsers. if you want to use it on NodeJS, you need to offer a `WebSocket` implementation and a `fetch` implementation.
-
-We decided to not include any of those dependencies on the SDK, keeping it as lightweight as possible.
-
-If you are coding in Typescript, which we recommend, you are going to inherit all the types from the Rocket.Chat server, so everything is going to be type safe.
-
-All types used on the server and original clients are going to be available for you to use.
-
-if you don't want to use realtime communication, you can use the REST API client directly: `@rocket.chat/api-rest`
-
-## Overview
-
-The sdk is implemented based on the following interface definition:
-
-```ts
-export interface SDK {
-	stream(name: string, params: unknown[], cb: (...data: unknown[]) => void): Publication;
-
-	connection: Connection;
-	account: Account;
-	client: ClientStream;
-
-	timeoutControl: TimeoutControl;
-	rest: RestClient;
-}
-```
-
-Which means that in case of any new feature, bug fix or improvement, you can implement your own SDK variant and use it instead of the default one.
-
-Each peace contains a set of methods and responsibilities:
-
-### Connection
-
-Responsible for the connection to the server, status and connection states.
-
-### Account
-
-Responsible for the account management, login, logout, handle credentials, get user information, etc.
-
-### ClientStream
-
-Responsible for the DDP communication, method calls, subscriptions, etc.
-
-### TimeoutControl
-
-Responsible for the Reconnection control
-
-### RestClient
-
-Responsible for the REST API communication for more info [see here][api-rest]