[CI] Set up GitHub Actions workflows for the remaining jobs

[palnabarun]

The current GitHub Actions lack the following compared to our Travis CI builds:

1. Functional tests.
2. Docs, pycodestyle, coverage
3. PyPI release

We need to add the same and disable Travis CI builds.

Action Items

• Functional Tests @palnabarun
• Documentation check (needs help)
• Pycodestyle check (needs help)
• Coverage (needs help)
• PyPI Release @palnabarun

[palnabarun]

/assign

[palnabarun]

We will try to pursue moving to Prow instead of GH Action to be in coherence with what the rest of the Kubernetes community uses for Continuous Integration.

/lifecycle frozen

[palnabarun]

Some updates here: We have moved the e2e tests from Travis CI to GitHub Actions as a stop-gap measure. We will continue moving pipelines to GH Actions and deprecate the use of Travis CI. The final goal still is to move everything to Prow.