add quota to LDAP
As analysed in #59 and agreed in the team, we will use quota rules per user.
Default quota is 200MB, which can be upgraded to 2GB (basic) or 20GB (pro).
Connect nextcloud, GroupOffice, DoveCot (IMAP) and Sandstorm with that quota field.
Provide web interface (keycloak?) so that an admin can set quota per user.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information