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
minor refactors, code comments
Rename interim to definitions
provide location of entry during init for definition
small fixups to set_temporarily
Refactor loop to use dict comprehension
Provide same interface for definitions
Make it work for composite lists
Check for sequence rather than a list
refactor tests
Fixes#4955Fixes#4957Fixes#4963
Saugat Pachhai (सौगात)
Batuhan Taskaya