License

[forslund]

Since the skill acceptance process seem to require a license file this PR adds

• a step in the skill creation to add a license file
• a check before uploading that the license file exists

It also adds a quick and dirty check that the main description is included in the readme.

Currently checks are only made on first upload, update of skills don't check anything.

This shouldn't be considered as final but it would be interesting to show if these kinds of checks would be of interest by the skill team.

[forslund]

I've now updated the PR from the feedback.

[krisgesling]

Awesome-sauce!