RTECO-1011 - Implement skill update all

[udaykb2]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
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****** THIS CHANGE BREAKS BACKWARD COMPATIBILITY ************

Summary:

Implementing skills update --all

• Currently we are having --all & --slug for plugins update
• We are taking that update behaviour from plugins & writing in skills

What --all does:

• It goes through all the folders in a path, gets the slug name, and updates them to the newest version
• It doesn't need --version, because it always updates to latest version
• --slug takes skill name as input & updates that specific skill

Commands:

jf agent skills update --all --harness cursor

jf agent skills update --slug autoagent --harness cursor