REPO: voltha-docs / make test -- updates needed to support python v3.10.4

NOTE: will be split into separate tasks later.

Problem #1) make html will fail if run w/o a persistent network connection:

1. Clone the voltha-docs repo.
2. Disconnect from the network
3. make - C voltha-docs html
4. Fail on external repo retrieval.

 × git clone --filter=blob:none --quiet https://github.com/zdw/robotframework-importresource /tmp/pip-req-build-b1412154 did not run successfully.
 │ exit code: 128
 ╰─> See above for output.

Problem #2)

The robotframework blob is an old hack that has gone stale.  Initially setup to workaround a problem with python v3.5 -> v3.6 migration (formatted print statement change).  Legacy code was also added for a now unspported version of ubuntu.  Remove the external dependency and update to the latest sphinx and robotframework pip modules.

Problem #3)

make test currently fails using python v3.10.4 (~venv) due to import problems:

• module collections.Mapper has been deprecated (temp rename to collections.abc)
• A separate issue with types/Union.py reported by a robot3 related python module.

Verify edits:

• cd voltha-docs
• make html
• make test

Check all repositories, very likely doc generation code has been reused – consider refactoring into a separate repository.