Other: fixed case issue in SSL member function names.
Other: removed 'restart' mention in SMTP and IMAP SSL settings.
GODT-1846: modified gRPC server to introduce ConnectionMode settings.
GODT-1846: implemented connection mode handling in bridge-gui.
GODT-1846: implemented error reporting in bridge-gui for connection mode.
Other: gathered all IMAP/SMTP server settings.
GODT-1846: wired IMAP/SMTP port change errors.
Other: Renamed some error events and signals.
Other: Fixed crash in IMAP restart when not started.
Other: dismiss port error notifications before changing ports.
Other: misc. fixes.
Depending on the timing of bridge closure, it was possible for the
IMAP/SMTP servers to not have started serving yet. By grouping this in
a cancelable goroutine group (*xsync.Group), we mitigate this issue.
Further, depending on internet disconnection timing during user login,
it was possible for a user to be improperly logged in. This change
fixes this and adds test coverage for it.
Lastly, depending on timing, certain background tasks (updates check,
connectivity ping) could be improperly started or closed. This change
groups them in the *xsync.Group as well to be closed properly.
