Move UCO ontology files to /ontology/uco

[ajnelson-nist]

This Pull Request resolves all requirements of Issue 387.

Review steps taken:

• [x] Pull request is against correct branch
• [x] CI passes in (CASE/UCO) feature branch
• [x] CI passes in (CASE/UCO) current unstable branch (merge-commit)
• [x] Impact on SHACL validation reviewed for CASE-Examples
• [x] Impact on SHACL validation remediated for CASE-Examples
• [x] Impact on SHACL validation reviewed for casework.github.io
• [x] Impact on SHACL validation remediated for casework.github.io

[ajnelson-nist]

A catch-up merge of develop has been done to resolve a Git conflict Github was reporting.