Remove a bunch of useless string_literal usage

Use a more precise return type, instead of auto

Remove all the empty “options” members in Column classes

By using SFINAE to use that member only when it exists.

Merge branch 'v4'

Everything was already cherry-picked, or something like that, so no changes
are involved, at all.

Add some scopes around various XmlSubNode

Add a global “persistent” option

Move a few functions from select_query to query

Set the database pointer to nullptr after a close

Re-implement correctly the handling of failure to open the database

If we can’t open it at startup, we exit.
If we can’t open it on reload, we keep the previously-opened database.

This way, we’re assured to always have a valid and open database available.

Remove a useless debug print in the e2e tests

Disable charybdis’ connection throttling

Add a Record History option in the Channel configuration form

fix #3269

Using OptionalBool, add RecordHistoryOptional col into IrcChannelOptions table

ref #3269

At startup, upgrade all database tables by adding missing columns

Fix cstdint -> cstddef, to fix compilation on freebsd

Explicitely declare the add_param<Id> specialization

Add a 0 default value for template argument N

Build the rpm with sqlite3

Don’t forget to bump to version 6.0~dev

Remove c-ares from the alpine image