Issue 544: Insert disjoint classes Endurant and Perdurant into hierarchy

[ajnelson-nist]

This Pull Request resolves all requirements of Issue #544 .

Coordination

• [x] Pull Request is against correct branch
• [x] Pull Request is in, or reverted to, Draft status before Solutions Approval vote has passed
• [x] CI passes in UCO feature branch against develop-2.0.0
• [x] CI passes in UCO current unstable-2.0.0 branch (1aac32a)
• [x] CI passes in CASE current unstable-2.0.0 branch tracking UCO's unstable-2.0.0 as submodule (ead959d)
• [x] Impact on SHACL validation reviewed for CASE-Examples
• [x] Impact on SHACL validation remediated for CASE-Examples (N/A)
• [x] Impact on SHACL validation reviewed for CASE-Corpora
• [x] Impact on SHACL validation remediated for CASE-Corpora (N/A)
• [x] Impact on SHACL validation reviewed for casework.github.io
• [x] Impact on SHACL validation remediated for casework.github.io (N/A)
• [x] Milestone linked
• [ ] Solutions Approval vote logged on corresponding Issue (once logged, can be taken out of Draft PR status)

[ajnelson-nist]

@plbt5 , how should we spell the inverses of the new properties?

[ajnelson-nist]

This PR has been updated to incorporate core:Event from #541 as a core:Perdurant subclass.

[ajnelson-nist]

Testing for adding core:Event to this PR has completed, with no troubles found in CI.

[ajnelson-nist]

Testing has been refreshed after shifting Endurant up above UcoObject.