Add type hints and/or reST docstrings

What is the idea?

A lot of the conda modules have no type hinting, incomplete type hinting, no docstrings, or docstrings with varying formats (reST, Google).

What should happen?

We should clean up the types and doc strings of one module or several small modules per PR until the code base has better documentation and type hints.

Type hints should follow mypy guide

Docstrings should follow Sphinx guide

Modules in progress:

(None)

Modules finished:

• conda.cli
  • main_info.py: #13445
  • main_search.py: #13465

### Tasks

- [ ] conda.base.* (0 finished, 0 in progress, 4 remaining)
- [ ] conda.cli.* (2 finished, 0 in progress, 24 remaining)
- [ ] conda.common.* (0 finished, 0 in progress, 21 remaining)
- [ ] conda.core.* (0 finished, 0 in progress, 12 remaining)
- [ ] conda.gateways.* (0 finished, 0 in progress, 27 remaining)
- [ ] conda.models.* (0 finished, 0 in progress, 10 remaining)
- [ ] conda.notices.* (0 finished, 0 in progress, 6 remaining)
- [ ] conda.plugins.* (0 finished, 0 in progress, 16 remaining)
- [ ] conda.testing.* (0 finished, 0 in progress, 11 remaining)
- [ ] conda.trust.* (0 finished, 0 in progress, 3 remaining)
- [ ] conda.*.py (0 finished, 0 in progress, 15 remaining)

auxlib removed from the list because it is currently being removed.