CB-6469 "plugin save" now records (path/url/registry) and ignores dependent plugins

Implements save and restore for plugins that are coming from local file system or from a git repo.
Also makes a change so that the dependency plugins are not saved during a save. Makes a change
on the fetch.js so that .fetch.json now accurately records the type for plugin installations from registry
as type 'registry'

github: close #86