Upload log files to the right location

Dependencies

• [2] OKQLN5AG Set proper charset on log files
• [3] FHVJYJFE Upload build logs to the binary cache
• [4] UVQJBDHN Move log compression to a plugin
• [*] MHVIT4JY Split hydra-queue-runner.cc more

Change contents

• replacement in src/hydra-queue-runner/builder.cc at line 157
  [3.335]→[2.0:129](∅→∅)
  − store->upsertFile("log/" + baseNameOf(buildDrvPath), readFile(result.logFile), "text/plain; charset=utf-8");
  [3.335]

  [3.449]
  + store->upsertFile("log/" + baseNameOf(step->drvPath), readFile(result.logFile), "text/plain; charset=utf-8");