Feature Request: Add support for the Identity property

[freundTech]

Currently whenever playerctl uses the name of a player it used the bus name. MPRIS2 also has a property called Identity on the org.mpris.MediaPlayer2 (Not org.mpris.MediaPlayer2.Player) interface, which gives a human readable name.

It would be nice to have an option to get the identity of a player (For example playerctl identity)

[acrisci]

What about a format variable?

playerctl metadata --format '{{playerIdentity}}'

[freundTech]

Yes. That would also work.

I just thought that because most things have both a command and a format variable and Identity isn't really part of the metadata having a command for it would be more consistent with the rest of the application.