Remove dependency on spectral-cube and parse ASDF/GWCS for JWST s3d cube

[pllim]

Description

This pull request is to remove dependency on spectral-cube and parse ASDF/GWCS for JWST s3d cube.

• Fixes nirspec ifu data fails to load in cubeviz with MJD errors #690
• Fixes Remove SpectralCube (Was: Build collapse method for Spectrum1D objects) #922

Blocked by:

• Spectrum1D translator does not accept GWCS when statistics is given glue-viz/glue-astronomy#59
• New specutils release beyond v1.5.0 for Spectrum1D.collapse().

Path forward:

• Split removing spectral-cube into a separate PR. See Remove dependency on spectral-cube #1006
• Instead of trying to load GWCS, we will just inject MJD-OBS ourselves in the Cubeviz parser for now, also a separate PR. See BUG: Recreate JWST MJD-OBS if it is missing #1004

Checklist for package maintainer(s)

This checklist is meant to remind the package maintainer(s) who will review this pull request of some common things to look for. This list is not exhaustive.

• Are two approvals required? Branch protection rule does not check for the second approval. If a second approval is not necessary, please apply the trivial label.
• Do the proposed changes actually accomplish desired goals? Also manually run the affected example notebooks, if necessary.
• Do the proposed changes follow the STScI Style Guides?
• Are tests added/updated as required? If so, do they follow the STScI Style Guides?
• Are docs added/updated as required? If so, do they follow the STScI Style Guides?
• Did the CI pass? If not, are the failures related?
• Is a change log needed? If yes, is it added to CHANGES.rst?
• Is a milestone set? Milestone is only currently required for PRs related to Imviz MVP.
• After merge, any internal documentations need updating (e.g., JIRA, Innerspace)?