RetroDECK log folder and enhanced logging.

[XargonWan]

• [ ] Move all the possible logfiles in ~/retrodeck/logs -> consider the comment below
• [ ] Symlink the other ones (ES-DE)
• [x] Put the log writing as a first line of retrodeck.sh (I already got a working line somewhere)
• [ ] Verbose the possible commands
• [ ] Write a log reader in the tools that gives the output of cat ~/retrodeck/logs/* in the Godot Configurator
• [ ] logrotate the old logs
• [ ] delete old log archives
• [x] post_update.sh move .logs in logs folder

[Lazorne]

Logs also need to be expanded to find update between old versions issues.

[XargonWan]

Maybe we should symlink the internal (.var) logs directories instead, as we don't know where retrodeck folder will be during the first installation, but we always know where the static log files are.