Fail2ban whitelist

[Gofannon]

Problem

• error in documentation made a nextcloud upgrade to fail (as fail2ban was broken, the upgrade failed)

Solution

• fix the doc
• proposal to enhance it

Solution long term

why not integrate the file yunohost-whitelist.conf in the "core" so people don't have to create it by hand . Could it be doable and where/how add it to the backlog ?

I have no idea of the "complexity" of it. Here is how I see it:

1. create the file
   1. copy the relevent part of fail2ban/jail.conf or take the one of this doc
   2. Create file https://github.com/YunoHost/yunohost/blob/dev/conf/fail2ban/yunohost-whitelist.conf
2. Add it to the "core"
   1. https://github.com/YunoHost/yunohost/blob/dev/hooks/conf_regen/52-fail2ban#L18
3. Problems
   1. how to manage existing whitelist config files and content ?
   2. Upgrades by YunoHost ?

• And how do you relevantly fix that problem

PR checklist

• I'm not doing a PR for an application, I promise, I know that this kind of changes must go directly into the app packages themselves
• PR finished and ready to be reviewed