Make the IRC channel configuration form available from the MUC config

fix #3250

Little fix and cleanup in the channels list code

Add an execute_incomplete_hello_adhoc_command e2e test

Group simultaneous JOINs into a single command, to avoid flooding

We still split the JOINs with a key and the ones without

Remove the e2e test for the linger_time

Revert "Add a linger_time configuration option on IRC servers"

This reverts commit 5d801ddcd025f68d2ec91edf0462091a32c779c1.

Fix the tests to take into account the new “your are exempt bla” line

Make sure the channel is joined before trying to leave it

fix #3243

Merge branch 'mam_default_limit' into 'master'

Limit of 100 MAM messages, if no other limit has been set by the client

Closes #3256

See merge request !9

Fix wrong JID computing when sending iq ping or version in fixed mode

fix #3259

Add an e2e test for the mam default limit

We send 150 messages, then retrieve the archive. We should receive messages
from 50 to 149 only.

Remove the flood limit in our e2e charybdis configuration

Handle the RSM "max" value in the MAM requests

fix #3255

Add an e2e test for the ad-hoc reload command

Properly handle multiline topics

fix #3254

Add an e2e test for the ad-hoc ping

Fix the display of the number of checks to be run by the e2e tests

Do not allow pings from resources that aren’t in the channel

fix #3252

Handle some iq of type='error' as valid ping response

fix #3251

Add the archive ID to messages when they are sent to users

This makes us compatible with mam 6.0

fix #3249