10288 Add keywordTermURI metadata in keyword block

[stevenferey]

What this PR does / why we need it:

To continue on the subject of OntoPortal integration

Which issue(s) this PR closes:

Closes #10288

Special notes for your reviewer:

In addition to the addition of the keywordTermURI field, the existing keywordVocabularyURI field is renamed to keywordVocabularyURL. We also added a script allowing administrators to optionally migrate data from keywordValue to keywordTermURI when the data starts with "http".

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

• The keyword metadata block is modified:

• Before data migration, here is an example with a keywordValue containing data starting with "http" :

• After optional data migration :

Is there a release notes update needed for this change?:

Yes, a proposal is visible in the file doc/release-notes/10288-add-term_uri-metadata-in-keyword-block.md