Use the Date to find a next page in RSM, not the id

This way, it works, whatever the order of insertion in the database was.

fix #3343

one log_debug -> log_error, also some trivial indent

Use a different Date data type

PLEASE backup your database before testing this commit, and report any
migration issue.

In postgresql, we use timestamp with timezone.
In sqlite3 we use REAL (the date is expressed as julianday)

This requires a migration of the muclogline_ table:
In postgresql it’s pretty simple, we convert all the integer into timestamps

With sqlite3, we actually rename the table, create the new one with the
correct type, then copy everything to the new table, with a conversion
function for the Date_ column, and then we delete the old table.

fix #3343

Channel disco-info: use shorter string

Change the nick of the joining user AFTER sending all the join stuff

fix #3305

Properly handle force-join presences by sending everything in return

fix #3305

Advertise the muc#stable_id feature on disco#info results

From XEP 0045:
“Note: the requirement to reflect the 'id' attribute was added in version
1.31 of this XEP. Servers following the new specification SHOULD advertise
that with a disco info feature of 'http://jabber.org/protocol/muc#stable_id'
on both the service domain and on individual MUCs, so that clients can check
for support.”

Reflect message IDs in channel MUCs

fix #3283

Remove the virtual channel feature altogether

Support the <before/> element in MAM requests

Do not forget an early return, to return the correct item-not-found error

Send a item-not-found error when the “after” value is not in the archive

Handle the “after” RSM value to page through results

Always return the oldest matching messages from MAM, even if no date is set

Remove the debug logs from previous commit

Add the complete='true' attribute only when appropriate

Do not forget the complete='true' attribute in MAM’s result iq

xep-0106 escape the JIDs listed in a disco#items server query

fix #3325

Fix a subtle iid parsing error in the adhoc code

Don’t answer to some requests towards MUC participants

These requests are only meant to be received by the room itself. The
participant must answer with not-implemented instead.

fix #3323