Feature/getting artifact details

[aguschin]

Implemented simple commands first.

$ gto which rf production -r pytest-cache/test_registry_state_tag_tag0
v1.2.3
$ gto which rf production -r pytest-cache/test_registry_state_tag_tag0 --path
models/random-forest.pkl
$ gto which rf production -r pytest-cache/test_registry_state_tag_tag0 --ref
7785e508c7d45b3b4112afbcce63308e29e5593c

$ gto latest rf -r pytest-cache/test_registry_state_tag_tag0
v1.2.4
$ gto latest rf -r pytest-cache/test_registry_state_tag_tag0 --ref
e3ae43afb6822cffc933e937e72c53024a2cb9e8
$ gto latest rf -r pytest-cache/test_registry_state_tag_tag0 --path
models/random-forest.pkl