build!: Rename the PyPI project to openedx-core

[kdmccormick]

Description

To represent the increasing scope of this repository, we are renaming it from openedx-learning to openedx-core. See the ADR for more details: https://github.com/openedx/openedx-core/blob/kdmccormick/openedx-core/docs/decisions/0021-openedx-core.rst

Practically, this PR:

• Updates GitHub hyperlinks in this repo from openedx/openedx-learning -> openedx/openedx-core
• Updates "Learning Core" to "Open edX Core" in various docs and comments
• Updates various docs and comments to represent the project's new scope.
• Publishes a new PyPI project called openedx-core, version starting at 0.34
• Publishes a final PyPI release of openedx-learning, versioned 0.33, which is empty and just installs openedx-core as a dependency

BREAKING CHANGE notice for operators: openedx-learning==0.33.0 will be the final release of openedx-learning. It will transitively install openedx-core==0.34.0 (fully code-compatible) and not receive updates going forward. In order to receive updates, operators should install openedx-core instead.

Notes for reviewers

• I think that I've updated pypi-publish.yml and tmp-openedx-learning/setup.py correctly in order to publish the openedx-learning final shell release. But, there's no easy way to test it without just running it. If it fails, I'll either do a quick followup PR, or I'll just log into PyPI and fix things up directly.
• Since the repo name is now openedx-core, I'm proposing that we rebrand it from "Learning Core" to "Open edX Core", with "OexCore" being an alternative spelling for use in code names. When we need to talk about the particular APIs, we just say "Content API" or "Core Content API", "Tagging API" or "Core Tagging API", etc. Here's an example in openedx-platform. Let me know what you think.

Supporting info / merge considerations / testing

Before merging this, we'll:

• Complete Unify smaller apps into one openedx_content app #454
• Complete Refactor so that openedx_content is a top-level package #468
• Rename the repo in GH settings so that the new links to openedx/openedx-core work

After merging this, I'll:

• Tag both v0.33.0 and v0.34.0
• Confirm that packages were pushed to PyPI correctly. If not, log in with our PyPI admin credentials and fix it up.
• Finish and merge build: Upgrade to openedx-core (renamed from openedx-learning) openedx-platform#38011
• Delete tmp-openedx-learning directory from this repo
• Grep for "openedx-learning" / "Learning Core" across the org and update

This is all part of:

• Rename this repo and PyPI project to openedx-core #470

[kdmccormick]

Suggested change

	When this repo was created, it was intended to only encompass learning concepts. The content models were supposed to be read-optimized LMS-friendly representations of learning content. It was imaged that the authoring models would live elsewhere (e.g. Blockstore). That's why this was called "Learning Core".
	When this repo was created, it was intended to only encompass learning concepts. The content models were supposed to be read-optimized LMS-friendly representations of learning content. It was imagined that the authoring models would live elsewhere (e.g. Blockstore). That's why this was called "Learning Core".

[kdmccormick]

Suggested change

	* This would make it harder to split apps out into separate repos, later because it would involve either (a) updating all the import statements or (b) having the ``openedx_core`` namespace split across multiple repos. We'd like to remain flexible with code reorganization given the fast-moving and experimental nature of these projects.
	* This would make it harder to split apps out into separate repos later, because it would involve either (a) updating all the import statements or (b) having the ``openedx_core`` namespace split across multiple repos. We'd like to remain flexible with code reorganization given the fast-moving and experimental nature of these projects.

[bradenmacdonald]

OK, looks good and the plan sounds good to me! I can't really test this but I looked over the diff and didn't see any issues.