Code cleanup and summary of changes.

Cleanup:
- Old code comments removed
- Debug comments removed
- Old log entries for debug removed
- Minor refactoring for readability

Overall summary of changes:
- Most of the communication with slapos is done using the Slapos Master Communicator instead of Slapos Controller:
  * supply, request, check instance status, check software status.
- Refactoring of related methods (waitInstance, isSoftwareReleaseReady, etc.)
- Initialization of communicator: initialize connection to SlapOS usign key and certificate
- Some related imports added
- General refactor: some unnecesary sentences and methods were removed.