Update README after project restructuring

### What change is being made

Update the README after changes introduced in
rai-inst/exploy#95.

### Why this change is being made

Provide update documentation.

### Tested

It's only a README file.

GitOrigin-RevId: aca85fcad09e651deefe9df585100bd4ec2a5cb3

Author: diegoferigo-rai