Clean up everything that is not stapi-fastapi

[jkeifer]

This PR aims to make this project easier for new developers to understand by removing everything not currently required for stapi-fastapi directly. The TLE backend has been moved out into it's own python package in a different repo: https://github.com/stapi-spec/stapi-fastapi-tle. The Landsat backend has been removed entirely, as its expected the TLE project can provide that same functionality (if this proves untrue we can always pull the Landsat backend out of the git history and move it into its own project).

All the docker/lambda/deployment pieces have been removed as they don't make sense for stapi-fastapi given its lack of any implementation.

The "scripts to rule them all" have been removed in favor of simply documenting the development commands in the README.

The stapi_fastapi directory has been moved under /src (https://packaging.python.org/en/latest/discussions/src-layout-vs-flat-layout/) and the test backend has been moved into /tests/backend.

The bump action has been removed in favor of using the poetry-dynamic-versioning plugin to get the version from git as proposed here.

[CloudNiner]

🎉 LGTM!

[jkeifer]

Turns out we do want to pull the Landsat backend out into it's own repo. I will make sure that gets done from the contents of this repo prior to this change.

[jkeifer]

Closes #53 and #72.