Add room setting which allows reacting when read only

...chat-channel-settings/client/views/channelSettings.coffee

packages/rocketchat-channel-settings/package.js

...hannel-settings/server/functions/saveReactWhenReadOnly.js

...t-channel-settings/server/methods/saveRoomSettings.coffee

...es/rocketchat-channel-settings/server/models/Rooms.coffee

packages/rocketchat-channel-settings/server/startup.js

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

packages/rocketchat-reactions/client/init.js

packages/rocketchat-reactions/client/methods/setReaction.js

packages/rocketchat-reactions/setReaction.js

packages/rocketchat-ui-message/message/message.coffee

server/startup/roomPublishes.coffee