[TASK] Show description of tests in Install Tool at start

The description of the following tests should be shown right away
instead after the test:

- Combining images
- Converting images
- Gdlib
- Scaling images
- Write gif & png

Furthermore the tag is used to highlight code.

Resolves: #79561
Releases: master
Change-Id: I90d1d3ff9f14cc193d4f67124e7a804085586106
Reviewed-on: https://review.typo3.org/51478


Tested-by: Riccardo De Contardi <erredeco@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>