feat: add cli for listing available patches

[MaferMazu]

Description

This PR adds tutor config patches list command with its functionality.

How to test

Run

tutor config patches list

Expected result:

PATCH                                          	LOCATIONS
caddyfile                                      	apps/caddy/Caddyfile
caddyfile-cms                                  	apps/caddy/Caddyfile
caddyfile-global                               	apps/caddy/Caddyfile
caddyfile-lms                                  	apps/caddy/Caddyfile
...
openedx-dockerfile-post-git-checkout           	build/openedx/Dockerfile
openedx-dockerfile-post-python-requirements    	build/openedx/Dockerfile
openedx-dockerfile-pre-assets                  	build/openedx/Dockerfile
openedx-lms-common-settings                    	apps/openedx/settings/lms/development.py
                                               	apps/openedx/settings/lms/production.py
openedx-lms-development-settings               	apps/openedx/settings/lms/development.py
openedx-lms-production-settings                	apps/openedx/settings/lms/production.py

If you had patches in a plugin patches (ex: You have defined caddyfile-mfe2 inside a caddyfile-global in a plugin):

PATCH                                          	LOCATIONS
caddyfile                                      	apps/caddy/Caddyfile
caddyfile-cms                                  	apps/caddy/Caddyfile
caddyfile-global                               	apps/caddy/Caddyfile
caddyfile-lms                                  	apps/caddy/Caddyfile
caddyfile-mfe2                                 	within patch: caddyfile-global
...

For more context about this PR: openedx-unsupported/wg-developer-experience#50

[regisb]

Looking good so far. Just let me know when you need a review.

[MaferMazu]

This is ready for review @regisb @kdmccormick

[regisb]

I really like your implementation, which is very lean and does not change the rest of the codebase. Also, the command output looks great and quite useful. Finally, I appreciate the fact that you took the time to write extensive unit tests.

Can you just address the comments and add a changelog entry? https://docs.tutor.overhang.io/tutor.html#contributing-to-tutor

[kdmccormick]

Nice work. The output looks great! I have no suggestions beyond what @regisb has already said.

[MaferMazu]

This PR is ready @regisb

[regisb]

just great!