Move all support for the legacy API into a plugin

[akhenry]

closes #4615

This PR renders support for Open MCT's legacy API optional by moving the entire adapter layer into a plugin.

Legacy support can be enabled by installing the new legacy support plugin like so:

openmct.install(openmct.plugins.LegacySupport());

If you also require support for legacy indicators you will also need to install the LegacyIndicatorsPlugin -

openmct.install(openmct.plugins.LegacyIndicators());

For now it remains installed by default in the Open MCT source. A followup issue has been filed to ensure that legacy support is disabled by default in 1.8.3.

In addition to moving legacy support into a plugin, this PR also:

• Adds a composition policy that was missing from the modern composition API to prevent composition of objects that do not support composability.
• Fixes a memory leak in timers that was causing problems in tests.
• Fixes a ton of tests broken by the removal of legacy code.

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Is this change backwards compatible? For example, developers won't need to change how they are calling the API or how they've extended core plugins such as Tables or Plots.

Author Checklist

• Changes address original issue?
• Unit tests included and/or updated with changes?
• Command line build passes?
• Has this been smoke tested?
• Testing instructions included in associated issue?

[codecov]

Codecov Report

Merging #4614 (f07dec3) into master (51e4c0c) will decrease coverage by 1.08%.
The diff coverage is 34.42%.

@@            Coverage Diff             @@
##           master    #4614      +/-   ##
==========================================
- Coverage   57.35%   56.27%   -1.09%     
==========================================
  Files         718      718              
  Lines       22772    22781       +9     
  Branches     1653     1653              
==========================================
- Hits        13061    12820     -241     
- Misses       9302     9551     +249     
- Partials      409      410       +1     

Impacted Files	Coverage Δ
src/plugins/condition/plugin.js	100.00% <ø> (ø)
src/plugins/legacySupport/BundleRegistry.js	75.00% <ø> (ø)
src/plugins/legacySupport/installDefaultBundles.js	40.00% <ø> (ø)
src/plugins/legacySupport/legacyRegistry.js	100.00% <ø> (ø)
src/plugins/legacySupport/plugin.js	0.00% <0.00%> (ø)
src/plugins/timer/components/Timer.vue	75.60% <ø> (+1.21%)	⬆️
src/utils/clock/Ticker.js	95.00% <80.00%> (-5.00%)	⬇️
src/MCT.js	97.80% <100.00%> (+2.52%)	⬆️
src/api/composition/CompositionAPI.js	100.00% <100.00%> (ø)
src/api/composition/DefaultCompositionProvider.js	81.81% <100.00%> (+0.86%)	⬆️
... and 52 more

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[github-actions]

Started e2e Run. Follow along: https://github.com/nasa/openmct/actions/runs/1603268815

[github-actions]

Success ✅ ! Build artifacts are here: https://github.com/nasa/openmct/actions/runs/1603268815

[unlikelyzero]

Note: This is passing our smoke tests.

[davetsay]

This is great @akhenry . I ran this in VISTA and there were no issues.

There are a couple of minor change requests inline.

[davetsay]

LGTM

Reviewer Checklist

Changes appear to address issue?	Y
Appropriate unit tests included?	Y
Code style and in-line documentation are appropriate?	Y
Commit messages meet standards?	Y
Has associated issue been labelled unverified?	Y