Issue 416: Change name of Event to EventRecord

[cyberinvestigationexpress]

Changed Event to EventRecord, and EventFacet to EventRecordFacet.

This Pull Request changes the EventFacet to EventRecordFacet, which resolves ambiguity raised in discussion of Issues #375 and #396 and #401.

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
• [x] CI passes in UCO current unstable branch (f4d3747)
• [x] CI passes in CASE current unstable branch tracking UCO's unstable as submodule (2058e66)
• [x] Impact on SHACL validation reviewed for CASE-Examples
• [x] Impact on SHACL validation remediated for CASE-Examples (N/A - Event not used)
• [x] Impact on SHACL validation reviewed for casework.github.io
• [x] Impact on SHACL validation remediated for casework.github.io (N/A - Event not used)
• [x] Milestone linked
• [x] Solutions Approval vote logged on corresponding Issue (once logged, can be taken out of Draft PR status)

[ajnelson-nist]

Converting to Draft until Solutions Approval vote is logged.