Resolve "Get rid of config directory"

Closes #89 (closed)
File rootmanager.dat is not needed any longer, as mpdsim is the default treename now
env.sh is moved into main dir, as SetEnv.sh will be removed soon along with old installation method support

DO NOT REMOVE THIS BOXED MESSAGE

Code in this merge request is subject to review by Code Owners.
The list of reviewers is posted in the comments section.
After all of the code is approved, please put a brief notice about it at the beginning of this message.

NOTE: Merging this code without getting it approved by Code Owners will result in suspending your developer rights!!!