logo and sounds fix for apache subfolder proxy (path must be relative to root url like http://domain.com/chat/assets/logo)

Closes #4184

Closes #6101

In the channel settings flex-tab, there is an exception in template helper: TypeError: Cannot read property 'get' of undefined, when read only is toggled.

* use katex from npm

* remove symlink

* Convert the majority of the integrations package to JavaScript

* Move the trigger handler to it's own class

* Start trying to generalize integration items

* Yay, additional events trigger outgoing webhooks

* Silence codacy and fix eslint problems.

* Started work on user created event for outgoing integrations

* Finish the outgoing integration work on the user created event.

* Add user join and leave room events for outgoing webhooks

* Add fields to the rest api integration creation and clean up the processWebhookMessage

* Add the HTTP to the incoming webhook context

* Don't check for property on result if it isn't there.
Closes #4175, #5762, and #5896.

* Add archive room and file upload events for the webhooks

* Disable integrations when the user to run/post as gets deleted.

* Try to fix the tests failing due to the requird events property

* Add history of integration which get fired

* Add the missing file for the IntegrationHistory

* Fix deleting users being broke due to my code

* Add the outgoing webhook integration history viewing page along with v1 rest api to retrieve it

* Integration history replays are now enabled along with advanced settings

* Work on the advanced settings and enable paging on the integration history

* Enable i18n for the history and advanced settings

* Update the wording on the word placement

* Move migration to be 88 now.

* Add missing translations for the webhooks

* Fix en.i18n.json identation

* Fix integrations.html indentation

* Fix more identations

* Fix identation of integrationsOutgoing.html

* added new send on enter setting

* add new preference and i18n values

* fix i18n

* changed to behaviour

Closes #5717

* Allow uploads to Google Cloud Storage

* Use the uniqueID instead of the hostname for uploads to google storage

* Fix admin combobox selection

* Fix addUserRoles and removeUserRoles only working for the first role

* Add setting for defining default roles for oauth registrations

* Suggested changes to improve readability

* added the ctrl+k search shortcut

* changed the placeholder of the the search

* small fix

* fixed i18n

* moved changes

* fix the if

Closes #6038