Object tagging 33

[matthewhilton]

Cherry pick of https://github.com/catalyst/moodle-tool_objectfs/pull/619 to MOODLE_33_STABLE

No major conflicts while cherry-picking, just namespacing and doc conflicts.

Testing

• Objectfs unit tests passing locally
• Ran through manual testing with S3 locally, working as expected.

Note about CI

• Ignore Ci - preexisting failure due to codechecker / phpdoc problems

[matthewhilton]

Closing as won't merge as this branch is too far out of date, but will leave branch as reference.