Add a model for managing permissions (power levels) in rooms. This gets rid of a whole bunch of boiler plate in NeoChat and as a bonus makes it easy to add a feature to allow setting the permission level for any event.
A category won't be shown if there are no relevant IDs (will add the ability to add new ones later).
Part of network/neochat#565
- Have LinkPreviewers stored in NeoChatConnection so that they don't have to be reloaded everytime the MessageContentModel is refreshed
- This means the link is never changed (it will be swiched for a new previewer with the new link)
- LinkPreviewers are stored by URL so they can be re-used by any event with the same URL
BUG: 484927 (because the offending code is ripped out)
This draws heavily on what @carlschwan did in network/neochat!1579 but I found it easier to start again and grab the bits as I needed them plus some other copying from what I did in the Space tree model.
From my current limited testing this seems to work nicely try and break it.
Shutup qt about below
```
SortFilterRoomListModel is neither a QObject, nor default- and copy-constructible, nor uncreatable. You should not use it as a QML type.
SortFilterRoomTreeModel is neither a QObject, nor default- and copy-constructible, nor uncreatable. You should not use it as a QML type.
SortFilterSpaceListModel is neither a QObject, nor default- and copy-constructible, nor uncreatable. You should not use it as a QML type.
```
Move the various room models into RoomManager. This means the same room models are always used and is a base from which further logic can be moved from QML to cpp.
Make sure that the neochat can handle switching connection when the current one is logged out. This is mostly about using QPointer to handle use after free issues due to room objects being deleted.
Steal the look of itinerary items from itinerary but simplified. Also includes new support for flights and restaurants
This adds previews for downloaded pdfs and code files.
UCHAR_EMOJI_PRESENTATION is replaced with UCHAR_EMOJI, which seems to be more useful for decting emojis.
The lambda is also turned into a proper function as there's no apparent reason for it to be a lambda.
Move the itinerary model representation to it's own component and instantiate from MessageComponentModel. This starts to lay some groundwork for previewing other files.
Stop space hierarchy being duplicated. This is done by making sure old jobs are cleared at all resets and to make doubly sure when a child is inserted it overrides itself so there can never be duplicates
Make sure that the new rules for counting notifications for muted, mention and low priority rooms is applied consistently to the room list, space drawer and the task manager notification badge
implements #644
