Change the `JoinRoomPage` so that it emits a `roomSelected` signal with the selected delegate's info instead of calling the functions to join or enter the room itself. This is so that the `JoinRoomPage` can be used for other purposes like selecting an existing child to add to a space.
We don't need to use a ToolBar for the titleDelegate since the
titleDelegate is already included inside a toolbar. This work magically
when using the default font size of 10px Noto Sans but breaks with 11px
BUG: 467242
Also modernize the codebase where possible (e.g use required properties,
reorder properties, fix warnings, don't use Action when not needed)
Signed-off-by: Carl Schwan <carl@carlschwan.eu>
