Improve logging, use log.group in ProductControl (bsc#1204625)

[lslezak]

Problem

• The installation log is hardly readable, it is difficult to navigate, it is not clear where each installation step starts and finishes
• Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1204625
• Related PR: https://github.com/yast/yast-ruby-bindings/pull/287

Review Notes

• Use the "Hide whitespace" diff option otherwise the diff is too long and harder to read.
• Simply use this link

Solution

• Use the new log.group call and group the logs for each executed step

Testing

• Tested manually
• See the example log from TW installation how it works (click the "Load URL" button to load the example log then scroll to the bottom)

[coveralls]

Coverage increased (+0.03%) to 41.719% when pulling 3f612ede625f27208da706370573e69d88575cc7 on logging into 13d6af4164ca32da51a2a5453a431a465d311d01 on master.

[yast-bot]

:x: Public Jenkins job #389 failed

[yast-bot]

:x: Internal Jenkins job #213 failed

[yast-bot]

:x: Public Jenkins job #390 failed

[yast-bot]

:heavy_check_mark: Public Jenkins job #391 successfully finished :heavy_check_mark: Created OBS submit request #1031177

[yast-bot]

:heavy_check_mark: Internal Jenkins job #214 successfully finished :heavy_check_mark: Created IBS submit request #283157