Add note to install Mutagen in documentation

[marcwieland95]

There's no note about how to install/use Mutagen.

It's only listed in the dependencies table, which isn't enough.

[tuxes3]

You can do that. 🙂

[Ruesa18]

@marcwieland95 do you think this is still a problem?
Is this about the actual installation of the software or about the configuration in the docker-compose.yml?

[marcwieland95]

We don't recommend Mutagen anymore, right? So mostly no special step is required

I think it was more about the README (Requirements section).
The README section File-Sync seems not 100% up-to-date (first sentence - unless Mutagen is set as default).

[Ruesa18]

@s4mpl3d Will we drop the Mutagen docs completely? Otherwise it might be a good idea to extend the README if it's not clear enough 👍
Although I don't think the installation of mutagen itself is not really a concern for this piece of software, since that has been documented in mutagens documentation. We could link there, though 🤔

But in general: dde-specific configuration is what we definitely should document. That's what I meant with my last comment @marcwieland95 . I tried to figure out if it is about mutagen in general or if it is about how to specifically use dde with mutagen 😉