Intermediate PR in removing path_info from our code base.
It is completely removed from the main codebase and is still
being used in tests, which will be migrated in the followups.
For fs-specific simple path manipulation, we've introduced
`fs.path` helper (similar to `os.path`).
Fixes#6774
* objects.status: use object IDs instead of naive objects
* objects.transfer: use object IDs instead of naive objects
* objects: add ReferenceHashFile
* odb: add ReferenceObjectDB
* repo: collect used object IDs instead of naive objs
* support basic/naive fs serialization
* objects.stage: stage file objects in addition to trees
* objects: remove save(), update transfer()
* output/dep: update for osave removal
* path_info: support both url and path attributes
* status/gc: use object IDs instead of naive objs
* diff: update staging usage
* commit: update staging usage
* tests: clean staging when needed
* tests: update for save/transfer/stage changes
* dvcfs: don't allow config serialization (repofs should be used instead)
* utils: return mtime as str, size as int
* tests: update unit tests for save/stage/transfer changes
* objects: use Repo.open when needed in ReferenceHashFile
* fix ls test staging
* objects.stage: don't skip hash check when loading from state
- individual hashes will still be loaded from state if they are still
valid
* ReferenceHashFile: serialize repo fs paths relative to repo root
* preserve state when staging
* objects.tree: skip hash computation in digest() when we have already
loaded hash from state
* always check file existence in referencehashfile
* update repofs test since stage no longer allows nonexistent files
* odb: only protect on check() if hash was verified
* staging: use unique memfs namespace for staging per dest ODB
* tests: clean full staging namespace
* refodb: preserve repofs cache dir
* repodependency: stage imports to local ODB and strict check circular
imports
* fetch: fetch staging last
* staging: make dest odb mandatory and preserve state
* refodb: cache nonlocal fs's
* fix rebase errors
* repofs: support full instantiation from fs config
* repofs: preserve subrepo factory for erepos
* tests: clarify repofs dirty file behavior
Ruslan Kuprieiev
Batuhan Taskaya
Peter Rowlands (변기호)