mod_c2s: Ignore unused event payload [luacheck]

mod_c2s,mod_s2s: Wait for sessions to close before proceeding with shutdown steps Ensures unavailable presence and other outgoing stanzas are sent. Waiting for c2s sessions to close first before proceeding to disable and close s2s ensures that unavailable presence can go out, even if it requires dialback to complete first.

mod_c2s: Close ports in a separate, earlier event from closing sessions Lets other things step in and do things while c2s ports are closed, e.g. mod_smacks, or other modules with port handlers that forward to c2s.

mod_s2s: Disable creation of new outgoing connections during shutdown

mod_c2s,mod_s2s: Disable and close port listeners before closing sessions This ensures no new clients can start connecting during shutdown

mod_posix: Run signal handlers in the startup thread

prosody: Expose main thread on the 'prosody' global To allow running things in it.

prosody: Run shutdown procedure in async thread

prosody: Move last cleanup and shutdown code into util.startup

mod_admin_shell: Squeeze some characters out of the Certificate column The more compact these are, the better