Plugin Support

...G...... [DEV-3542] removed plugin system options and split unmarshal into strict and non-strict functions

* commit 'bf2487d06c77fb9c3e2aa7e09970209ed78c665a':
  ...G...... [DEV-3542] fixed PR comments
  ...G...... [DEV-3542] fixed PR comments
  ...G......[DEV-3542] split conf unmarshal and removed plugin system options structure