Modify generate_build_report to use the new dictionary instead of a log file

The following discussion from !54 (merged) should be addressed:

• @clemenci started a discussion:

  About the frontend understanding the new structure, we first have to change generate_build_report to use the new dictionary as input instead of the dump.

  At that point we should decide how we format the new report and teach the frontend to display it.

  But in another MR.