The `mpris-player` crate has been deprecated upstream in July 2022. The
best alternative currently is `mpris-server`, which is actively
maintained, published on crates.io and has an API very similar to the
one from `mpris-player`.

The main differences are the following:
* the `Player` object, once created, must be initialized and run in an
  async block, requiring a new task to be spawned
* most setters are async as well, with the same side effect (spawn new
  tasks)

This change is a straightforward port, partly inspired (for the async
operations) by Mousai.

Fixes #267