This MR aims to apply a re-designed plugin infrastructure that allows easier plugin development. Important changes:
- Plugins are initiated with an already initiated PodClient
- No persistent state/storage for plugins
- Plugins are fed with account -if required- or any other config/information through PluginRun
- Plugin runtime state is set and communicated via its PluginRun
- Authentication via new authenticators module: 1st one is OAuthAuthenticator