feat: merge ckanext-zarr as a subtree

[ChasNelson1990]

Description

In order to reduce the number of commits, PRs and everything else - I have merged the git tree for ckanext-zarr into this repository.

The structure of the folder and all files remains the same.

~I have moved the .github folder from the extension into the root of this project and updated it so that the Pipfile is used and tests are run on PRs in this repo.~ edit: I have been unable to get the GitHub Action tests working due to seeming incompatibilities with the ckan base image and pipenv.

Dependency Changes

Removes the submodule dependency.

Checklist

• [ ] The Jira ticket for this issue has been updated to "Ready to Review" or equivalent.
• [x] I have developed these changes in discussion with the appropriate project manager.
• [x] My code follows the general Fjelltopp documentation (see Confluence).
• [ ] I have made corresponding changes to the Fjelltopp documentation (see Confluence).
• [x] I have rebased this branch with master.
• [x] New dependency changes have been committed.
• [ ] I have added automated tests that prove my fix is effective or that my feature works.
• [ ] New and existing tests pass locally with my changes.
• [x] My changes generate no new warnings.
• [x] I have performed a self-review of my own code.
• [x] I have assigned at least one reviewer.
• [ ] I have assigned at least one label to this PR: "patch", "minor", "major".

[ChasNelson1990]

I would be up for discussing this and what I was trying to do on Monday if people are free?

[ChasNelson1990]

Marking as not draft so Jenkins will build it