browse: Disambiguate URLs related to origin / snapshot context browsing

Disambiguate and/or deprecate the following browse URLs:

  - GET /browse/origin/(origin_url)/content/(path)/

  - GET /browse/origin/(origin_url)/directory/(path)/

  - GET /browse/origin/(origin_url)/visit/(timestamp)/branches/

  - GET /browse/origin/(origin_url)/visit/(timestamp)/content/(path)/

  - GET /browse/origin/(origin_url)/visit/(timestamp)/directory/(path)/

  - GET /browse/origin/(origin_url)/visit/(timestamp)/log/

  - GET /browse/origin/(origin_url)/visit/(timestamp)/releases/

  - GET /browse/snapshot/(snapshot_id)/content/(path)/

  - GET /browse/snapshot/(snapshot_id)/directory/(path)/

Replace their use by providing timestamp and path as query parameters to these endpoints
for consistency:

  - GET /browse/origin/(origin_url)/content/

  - GET /browse/origin/(origin_url)/directory/

  - GET /browse/origin/(origin_url)/log/

  - GET /browse/origin/(origin_url)/branches/

  - GET /browse/origin/(origin_url)/releases/

  - GET /browse/snapshot/(snapshot_id)/content/

  - GET /browse/snapshot/(snapshot_id)/directory/

Update endpoints documentation to reflect these changes.

Closes T2115
Closes T2135