This commit replaces `CategoryList` and `ChannelList` with `StatusChatListAndCategories`,
`StatusPopupMenu` etc. provided by StatusQ.
It also removes components that lived inside Status Desktop but are no longer used
anywhere after the refactor.
Since StatusQ components are decoupled from UI model logic, we also needed to introduce
a new API retrieve a community category from within QML.
Closes#2805
Pascal Precht
Jonathan Rainville
Richard Ramos
Iuri Matias