[NEW] Enable/disable Livechat registration form fields (#10584)

packages/rocketchat-i18n/i18n/en.i18n.json

packages/rocketchat-i18n/i18n/pt.i18n.json

packages/rocketchat-livechat/.app/client/lib/_livechat.js

packages/rocketchat-livechat/.app/client/lib/commands.js

...s/rocketchat-livechat/.app/client/views/livechatWindow.js

packages/rocketchat-livechat/.app/client/views/register.html

packages/rocketchat-livechat/.app/client/views/register.js

...ketchat-livechat/client/views/app/livechatAppearance.html

...ocketchat-livechat/client/views/app/livechatAppearance.js

packages/rocketchat-livechat/config.js

packages/rocketchat-livechat/server/lib/Livechat.js

...ages/rocketchat-livechat/server/methods/getInitialData.js

...ages/rocketchat-livechat/server/methods/saveAppearance.js

...etchat-livechat/server/publications/livechatAppearance.js