mod_admin_telnet: Document HTTP command in internal help

mod_admin_telnet: Document (in the internal help) debug commands

mod_admin_telnet: Pretty-print values returned from commands This makes it much nicer to inspect Prosody internals. Existing textual status messages from commands are not serialized to preserve existing behavior. Explicit serialization of configuration is kept in order to make it clear that returned strings are serialized strings that would look like what's actually in the config file. The default maxdepth of 2 seems ought to be an okay default, balanced between showing enough structure to continue exploring and DoS-ing your terminal. Thanks to Ge0rG for the motivation to finally do this.

mod_carbons: Check for and strip 'private' tag before stopping This was explicit previously

mod_carbons: Don't copy messages that should not be copied The return statements were lost in d95e083931d1

Merge 0.11->trunk

mod_tls: Log when certificates are (re)loaded Meant to reduce user confusion over what's reloaded and not.

mod_carbons: Carbon anything that has been archived by the current user This ensures rules in mod_mam apply to some extent. Messages worth archiving are probably worth sending to other clients.

mod_carbons: Carbon incoming message delivery failure reports Ensures that all your clients know about sent messages that failed.

mod_carbons: Fix syntax error [luacheck]