add logrotation option

Hi,

awesome playbook, but i'd like to see a configurable option to add nextclouds internal logrotation. since nc14 or so it is enabled by default even if not listed in the config.php, but is set to 100MB as rotation breakpoint.

nextcloud-logs (the json log at data/nextcloud.log) is quite unreadable anyways, but if you'd like to have smaller logs (or if they remove that default somewhen) you'd want to have this configurable. the occ-command for this is as follows:
sudo -u www-data php /var/www/nextcloud/occ log:file --rotate-size 10MB
you can use human-readable sizes here, however, it goes as bytes to the config.php :
'log_rotate_size' => 10485760,
i'd try to add this by my self, but i'm still learning how to be good at especially idempotency :-)

Start by examining the playbook tasks that manage Nextcloud's config.php and the documented occ entry point sudo -u www-data php /var/www/nextcloud/occ log:file --rotate-size 10MB. Done should provide a configurable log-rotation size that results in the corresponding log_rotate_size value in config.php while remaining idempotent.