Feature/refactor day1

[theFeu]

Main Topics:

• Smoother Start into Git core concepts
• Add more GitLab Topics on day1
• Add more GitLab Labs on day1
• Reword a lot of slides to be clearer
• Move git tag to end of day and finish the day with a git tag v0.5 -m "End of Day One Release"
• Remove Create NMS GitLab Labs (as discussed)

Also:

Fixes #217

Fixes #214

[martialblog]

@theFeu @htriem @mocdaniel For my part the Day1 refactor is done. Unless I find typos I won't be touching the day1 Slides anymore.

Feedback is welcome.