feat: Add utility for logging sensitive information using encryption

[timmc-edx]

Description:

This is copied from edx-platform, and was introduced there in https://github.com/openedx/edx-platform/pull/29682. Bringing it out into this library will allow it to be used across IDAs, and in particular in the cookie monitoring middleware.

Introduces log_sensitive module for public-key encryption of sensitive debug information in log messages, including CLI commands for generating keys and decrypting log output. Exposes log_sensitive in logging module.

Changes from original:

• New CLI check to warn on inclusion of [encrypted: ...] wrapper, since I've made that mistake myself a few times. (Not sure if it's worth automating removal, since there are probably a few variations on it.)
• Update docstring to use correct module name (after move)
• Tweak to gen-keys language that I felt was a little confusing
• Test full CLI of log_sensitive (although had to mark as no-cover since sometimes coverage doesn't manage to detect what the subprocess code runs.)

Also:

• Expose as log-sensitive in CLI, since the code is now in an internal module.
• Add a Logging README (including for existing log filters code)
• Alphabetize main README's table of contents

ref: ARCHBOM-2082

JIRA:

ARCHBOM-2082

Merge checklist:

• [x] Version bumped
• [x] Changelog record added
• [x] Documentation updated (not only docstrings)
• [x] Commits are squashed

Post merge:

• [x] Create a tag
• [x] Check new version is pushed to PyPi after tag-triggered build is finished.
• [x] Delete working branch (if not needed anymore)

[timmc-edx]

Note for reviewers: Probably best reviewed commit-by-commit:

• First commit is a straight copy of the src and test files, plus a dependencies change
• Second commit makes some tweaks (see commit message)

[timmc-edx]

Ah right, I remember now that I had a question about that: If I just move this into internal and expose encrypt_for_log, then the CLI commands will have to call edx_django_utils.logging.internal.log_sensitive or something. But the CLI isn't internal... Thoughts on that?

[timmc-edx]

Hmm, maybe I can make it a command/entry-point/whatever it's called, in setup.py.