Add --details flag to mlem ls

[aguschin]

Would be nice to see not only models, but also additional information, like

• commit hash which changed the model last time
• commit author
• commit date
• model type, e.g. ML framework, or, in case of dataset, data wrangling library, and maybe model version
• other relevant info from meta.yaml

This maybe achieved by using several flags, so we need to discuss design in more details and draft some examples first.

[mike0sv]

Related to #94