Everruns CLI plugins, skills and knowledge-bases commands work again

The everruns plugins, everruns skills and everruns knowledge-bases commands sent requests to /plugins, /skills and /knowledge-bases, which the server does not serve, so they failed with 404. They now call /v1/plugins, /v1/skills and /v1/knowledge-bases for both list and per-item requests.

See CLI: plugins, CLI: skills, CLI: knowledge-bases and #3326.