refactor: use the npm workspace packages/* pattern and rename e2e subpackage

[ozyx]

Closes #7918

Describe your changes:

This PR reorganizes the e2e testing infrastructure by moving it into a proper npm workspace package. The changes are primarily structural and do not modify the functionality of the tests themselves. The purpose is to completely prepare our e2e testing framework for publication as a separate package, and update our usage of npm workspaces to have a maintainable structure that can be expanded upon in the future.

Key changes include:

• Moved all e2e test files from /e2e to /packages/e2e
• Created proper npm workspace package structure with @openmct/e2e package
• Updated all related file paths and references throughout the codebase
• Updated CI/CD configurations to reflect new directory structure
• Updated test output and coverage paths

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 a notable change that will require a special callout in the release notes? For example, will this break compatibility with existing APIs or projects that consume these plugins?

Author Checklist

• Changes address original issue?
• Tests included and/or updated with changes?
• Has this been smoke tested?
• Have you associated this PR with a type: label? Note: this is not necessarily the same as the original issue.
• Have you associated a milestone with this PR? Note: leave blank if unsure.
• Testing instructions included in associated issue OR is this a dependency/testcase change?

Reviewer Checklist

• Changes appear to address issue?
• Reviewer has tested changes by following the provided instructions?
• Changes appear not to be breaking changes?
• Appropriate automated tests included?
• Code style and in-line documentation are appropriate?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 57.14%. Comparing base (2010f2e) to head (1834963).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7916      +/-   ##
==========================================
- Coverage   57.66%   57.14%   -0.53%     
==========================================
  Files         677      677              
  Lines       27373    27373              
  Branches     2689     2689              
==========================================
- Hits        15786    15643     -143     
- Misses      11248    11388     +140     
- Partials      339      342       +3     

Flag	Coverage Δ
e2e-ci	62.48% <ø> (+0.51%)	⬆️
e2e-full	23.46% <ø> (-34.67%)	⬇️
unit	49.30% <ø> (-0.06%)	⬇️

see 17 files with indirect coverage changes

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