document changes implemented in https://issues.redhat.com/browse/RHIDP-3569

this should be a subsection in the dynamic plugins guides

• how to configure the PVC for dynamic plugins cache
• what triggers a new installation of plugin
• how to force a download of a plugin

contact is Marcel Hild and Tomas Kral for more information

Draft doc from Marcel Hild: https://gist.github.com/durandom/139a916f55c1bb666ad5425ef57635fc