Decouple front-end (Svelte) from "mockapi" to allow other plugins

Problem/Motivation

As there is more progress into the plugin system (so we can switch between mock data vs real data and endpoints), we need to make sure that new additions to Svelte files do NOT rely on IDs or labels only present in the mock data.

Things like this should be avoided at all costs. Instead, it should be an endpoint where you read that data, and then you iterate through the IDs and the labels.

Steps to reproduce

Get the latest version of 1.0.x and see code like this:

    let developmentVocab = {
        UNDER_ACTIVE_DEVELOPMENT: 9988,
        MAINTENANCE_FIXES_ONLY: 13030,
        NO_FURTHER_DEVELOPMENT: 16538,
        OBSOLETE: 9994
    };
    let developmentLabel = {
      9988: 'Active',
      13030: 'Maintenance Only',
      16538: 'No Further Development',
      9994: 'Obsolete'
    }

This is data from the mock fixtures and will never work with another plugin reading from actual endpoints.

Proposed resolution

Create new endpoints for data that can be needed and have Svelte read from the endpoints and then iterate through the results.

Remaining tasks

• ✅ File an issue about this project
• ☐ Addition/Change/Update/Fix to this project
• ☐ Testing to ensure no regression
• ☐ Automated unit/functional testing coverage
• ☐ Developer Documentation support on feature change/addition
• ☐ User Guide Documentation support on feature change/addition
• ☐ Code review from 1 Drupal core team member
• ☐ Full testing and approval
• ☐ Credit contributors
• ☐ Review with the product owner
• ☐ Release

User interface changes

Svelte files will need to be refactored.

API changes

A few. New endpoints will be needed.

Data model changes

Not really if we encapsulate data in the plugin. It can return a hardcoded array, as long as that's in the plugin and not the svelte files.

Release notes snippet

Decouple front-end from the source of data so we can exchange between mock and real endpoints.