Reduce the number of submodules to form a core API

[david-waltermire]

User Story:

As a Metaschema I need to load a Metaschema. This should be core functionality. At the moment I need multiple dependencies.

Consider relocating the code in the metaschema-model module to the metaschema-model-common module.

The new combined module could be called metaschema-core.

Goals:

For the 1.0 release:

• Create a new metaschema-core module.
• Move the metaschema-model to the core.
• Move the metaschema-model-common to the core.
• Ensure the proper relocation entries are created.
• Update all dependent modules.

Dependencies:

None.

Acceptance Criteria

• All website and readme documentation affected by the changes in this issue have been updated. Changes to the website can be made in the docs/content directory of your branch.
• A Pull Request (PR) is submitted that fully addresses the goals of this User Story. This issue is referenced in the PR.
• The CI-CD build process runs without any reported errors on the PR. This can be confirmed by reviewing that all checks have passed in the PR.