Troubleshoot: Run the building tool with only one user

### Background

There's no reason to run the building tool (`sbt`) with super user permissions.

Running the build with sudo (root user) or any other user will generate the target folder owned by that user.
Then if you run with another user this can lead to unintuitive permission errors. Like #216

### DoD
- The troubleshoot SHOULD help the user
- know that he should not run as a super user (giving an example of the no intuitive errors)
- solve the original problem mention on #216. User clone as repo as user A and is run as User B (without permissions on the folders)

### Implementation Details/Hints
- Add to the troubleshooting section in [README.md](https://github.com/hyperledger-identus/mediator/blob/main/README.md) with some of those errors.
- Mentioned that the user should not run SPT as a super user
- Add a way to fix it #216. By doing a clean `git clone ...`, or run `sbt clean` or even by changing every single file on the folder `chown -R USER:GROUP atala-prism-mediator`