Drop Python 3.7 support, and replace with Python 3.8
Resolves: #21532
/vscode-python/requirements.txt generated same hash even when running:
```pip-compile --generate-hashes requirements.in```
from the Python3.8 virtual environment.
- Same result with pythonFiles/jedilsp_requirements/requirements.txt when running:
```pip-compile --generate-hashes
pythonFiles/jedilsp_requirements/requirements.in```
Cleaning up smoke test dependency: See if all Github action test pass
with removing the smoke test requirement file content.
Checked one by one, and came to see removing all doesn't seem to have
impact on the outcome of running smoke test.(Seems to have no difference
in smoke test result outcome when ran with "Run and Debug" in VS Code
with smoke-test option selected).
Also got rid of below, after checking smoke test correctly passing after
removal of smoke-test-requirement.txt content:
Resolve: #21496
Dev container rewrite using MCR.
Pyenv for installing and managing python versions. Fish also installed
as optional (able to view as shell option in codespaces). Also fixing
conda error. Takes care of: #21591 rewrite from: #21435 to adhere to
company policy.
Anthony Kim