185 ship schema with package

[marc-white]

This PR closes #185 by incorporating the schema descriptions (JSON) into the package. This has been done IAW what I think is current best practice for storing & loading data files within a package (https://docs.python.org/3/library/importlib.resources.html#module-importlib.resources).

Whilst doing this, I found a couple of places where the data submodule was doing some ad-hoc local data loads. These have also been updated to use the new pattern.

Open questions:

• Is this how we want to ship schema? How often do the schema need updating, and is it a pain to have to tag a new version every time an update is required?

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.95%. Comparing base (a07470a) to head (bf43d6d). Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/access_nri_intake/cli.py	50.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #189 +/- ## ========================================== - Coverage 96.96% 96.95% -0.02% ========================================== Files 9 9 Lines 626 623 -3 ========================================== - Hits 607 604 -3 Misses 19 19 ```

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[aidanheerdegen]

Let me know when you want another review @marc-white