See discussion: #1186

See also https://listes.renater.fr/sympa/arc/sympa-fr/2020-11/msg00040.html

Upgrade process may fail inserting records in the `list_table` table, due to the `searchkey_list` value overflowing that column size (`varchar(255)`).
Truncates that field, to ensure upgrade doesn't skip anything.

Wild guess / maybe there's other places we could do this.
Found out a mention of that issue over there: https://listes.renater.fr/sympa/arc/sympa-fr/2019-10/msg00017.html
As of patching that file on my server, I can re-run the upgrade (from 5.4.7 to 6.2.40),  without any mention of such failures.

There is no save method in Sympa::List anymore.

* review: Won't process sync_include in advance so that processing will be faster.

* Refactoring. Sympa::List::on_the_fly_sync_include() was removed. Instead, "include" request handler had "delay" option.

* Remove unused "last_sync" cache entries.  "last_change" entries remain.

* sync_include will no longer be invoked during Sympa::List->new():
  - No owner defined in a list is no longer treated as error_config.
  - Instead, if no owner defined,
     - If possible, discard incoming message and send back DSN to original sender,
     - or, notifications to owners will be redirected to listmaster(s).

* Refactoring: Remove unused functions

* Small refactoring: mail_tt2/listeditor_notification.tt2 is no longer used.

* Clarify log messages and DSN about undefined owner/editor/listmaster

Fix: List::load() does call check_param_constraint(). This is not required; check_param_constraint() only make sense when a family list gets re/instantiated. These calls are very expensive for institutions heavily using families. Our production list service has 2.500 lists; most of them belonging to a family. In these circumstances wwsympa.fcgi startup takes 3 minutes. Applying this patch lowers wwsympa.fcgi to 35 seconds. Much better. I did some tests to ensure this patch does not prevent param_constraint checking while instantiating, modifying, adding lists to families. My tests (based on Test::BDD::Cucumber) are public on https://github.com/salaun-urennes1/sympa-functional-tests

Fixed by correcting query.

These log messages are not useful for normal debugging and are cluttering the logs unnecessarily.

[bug] mtime for cache file like .last_change.admin on some filesystems like NFS with Linux was not updated.  Fixed by updating it explicitly with utime().

In add_list_member the value $current_list_members_count is discarded if max_list_member == 0 (default setting).
This prevents the "high db load" produced by the successive DB accesses.

When changing a list's admin two times in the same second, the list admins cache is not updated. Consequently, when trying to add a third admin in the same second, the second one is not in the cache at the time.
Obviously it does not sound like a recurrent scenario and I met this problem when running a test file only.
However, it is possible that this happens more often when trying to make batch modifications in the shell. And also, it made my test fail which is an engineering problem: it could be misguiding about the cause of a test failure.
So I changed the expiration test, replacing "<" by "<=" and it solves the problem.
I don't see any side problem that could result from this change bu I commit it separately anyway because the cache is very sensitive.

Replace Sympa::List::load_list_of_scenarios() with Sympa::Scenario::get_scenarios().