fix: creates linting-typing.cfg in presubmit

[chalmerlowe]

This PR creates a new configuration file in the .kokoro/presubmit folder.
The intent is to eventually move multiple checks out of the baseline Kokoro check and put them into their own Kokoro linting-typing:

The checks we are moving out include:

Typing:

• mypy
• mypy_samples
• pytype

Linting/formatting:

• lint
• lint_setup_py
• blacken

[conventional-commit-lint-gcf]

🤖 I detect that the PR title and the commit message differ and there's only one commit. To use the PR title for the commit history, you can use Github's automerge feature with squashing, or use automerge label. Good luck human!

-- conventional-commit-lint bot
https://conventionalcommits.org/

[chalmerlowe]

There is an internal Google CL (#618137967) to update the allowed env vars for this repository.
Once that gets approved, we should be able to confirm that this PR runs and determine what, if any time-savings are achieved by parallelizing these tests.

[shollyman]

Thanks for simplifying this a bit!

[chalmerlowe]

updated the comments.