Merge pull request modoboa#2504 from modoboa/fix/valid_mxs

Valid MXs field must contain only IPs.

Fixed wrong deploy path for frontend.

Fixed packaging issues.

Updated workflow

Removed old reference to stats plugin in doc.

Enable policyd for new deployments.

Updated setup.py

Good fix this time?

Changed message field type to TextField. (modoboa#1754)

fix modoboa#1743

Added 1.13.1 documentation.