feature: add PBS Tape metrics

[Mikec78660]

Would be great if you could export tape data.

Libraries
Media Pools
Number of tapes in each media pool
number of full tapes in each media pool
etc.

[janfuhrer]

Hi @Mikec78660 at the moment this is not planned from our side as we cannot test it either (as we have no tapes).
Feel free to create a merge request if you want.