dRNG refactor (#727)

*  Flatten drng package

*  Fix linter warnings

*  Refactor dRNG plugin, API and dashboard

* 

 Address review comments

* refactor: Rename Parse_ functions to _FromMarshalUtil for consistency

* fix: Fix typo

* fix: Fix comments

Co-authored-by: jkrvivian <jkrvivian@gmail.com>