Fixed issue with shell user creation due to missing parent user and group values in shell_user database records.

- Use it like $app->conf('yourpluginname', 'config-key', 'value')
- omit the value to read the config value, provide it to set the value

- database users
- email forwarders and aliases
- clients

- Added email message templates.

- Fill IP select fields with IP from correct server even if the user's default web server is another server. Otherwise if the user opens the web form, the wildcard * is selected, and if he changes the tab, the wildcard is saved instead of the correct IP so that the website will no longer work.

- nginx pm settings: values were limited to 3 figures (so max. value was 999), increased this to 6 figures.

- Added section toggle for client limits

- Resellers can use templates for their clients.

- Add config to clear php handler in apps vhost.

- Added options to use a mounted backup directory. This allows for remote backups, e.g. vis sshfs to a backup server. The backup script checks if the backup directory is mounted, and if not, tries to mount it.

Removed workarounds

Fixed login as

- Added fields to client, reseller and website to show when a record was added and by which user