Model documentation updates

[constantinpape]

The links to the v3 models are not correctly given here: https://computational-cell-analytics.github.io/micro-sam/micro_sam.html#other-models.

For this we need to link to previous versions on BioImage.IO and I am not quite sure how to best do that.

[constantinpape]

We should also:

• Extend the documentation for the available models in micro_sam.info, to indicate which model is used (i.e. the version), and ideally provide a link with more info for each model.
• 'Advertise' the micro_sam.info command more prominently. E.g. when starting the GUI and in the documentation.

(Good feedback from Carsen)

[anwai98]

• Add FAQ for how to (custom) load models in micro-sam