Docs : plugin choices

[almereyda]

In many scattered places, there are suggestions which additional plugins can or should be installed alongside the default modoboa-installer distribution. These need to be known for a concise upgrade procedure or customized setups.

• modoboa-radicale suggesting to make it mandatory in the official installer package. After creating a postmaster@FQDN alias plus a root@FQDN one, the linked issue appears.
• modoboa-sievelib which is not part of the collection of default extensions
• modoboa-dmarc which is part of the component ecosystem modoboa, not to be confused with its core.

If all of these, installed or available, would be visible from /core/#info/, one could start thinking about an auto-update mechanism, guided updates via the UI or even a small integrated package manager of modules.

[almereyda]

The modoboa-radicale integration via installer.cfg is also partly incomplete, as plainly adding it to the extensions doesn't provide and configure the radicale server as well as the rights file's path according to the home_dir.

[tonioo]

I do agree that the documentation could be improved. About your points:

• modoboa-sievelib does not exist. The sievelib package is totally independent from modoboa (even if I created it too) and is already declared as a requirement of modoboa-sievefilters (https://github.com/modoboa/modoboa-sievefilters/blob/master/requirements.txt)
• I've just discovered a little mistake about the radicale plugin, I'm going to fix it. Anyway, you're right about radicale, the setup is far from complete and that's why it is not enabled by default with the installer. This is clearly an enhancement to make.