adds bootstrap results to debug log

[shelane]

Fixes #4127

Changes proposed

Add Drupal bootstrap results to the debug log output so that when running command with verbose, developers can see what the actual result was.

Steps to replicate the issue

if ($this->getInspector()->isDrupalInstalled()) {
        // Run update.
        $this->invokeCommand('artifact:update:drupal');
        $this->sendMMNotification("{$multisite} site update complete on {$environment} ({$loop} of {$total}).");
        $loop++;
      }
      else {
        $newinstall[] = $multisite;
      }

Previous (bad) behavior, before applying PR

Running the above in a custom command, I'm seeing all sites of a multisite getting put into the newinstall array. During my run, all of the sites are existing sites and the bootstrap status check should be returning successful. I need to debug further.

Expected behavior, after applying PR and re-running test steps

[debug] Drupal bootstrap results: Drupal bootstrap : Successful

[danepowell]

Thanks for the PR!