New comment by ProjectMoon on void-packages repository

https://github.com/void-linux/void-packages/pull/22810#issuecomment-662682603

Comment:
Some rather major changes to this PR, based on the suggestions of @ahesford: 
 
* The `radicale3` package was removed, and instead the `radicale` package now has radicale3.
* The `radicale2` package has been turned into a transitional package pointing to `radicale`.
* Essentially, we are dropping `radicale2`, and using the original package to upgrade to the latest version of Radicale.
* Configs for Radicale placed in `/usr/share/examples` in case of upgrade from old versions when `/etc/radicale` is not touched.
* Updated `INSTALL.msg` for Radicale.

`etesync-dav` upgraded to 0.20.0, and depends on the upgraded `radicale` package.