Makes the Pull Request template a bit more explicit.
Goals of this are:
- to guide the user more
- to make it more clear what we are asking for (e.g. what kind of tests)
- to ask for code examples (that could be used for documentation)
- to start a thought process for the contributor
- to make the maintainers work a bit easier
Addiotionally we formatted the links in the checklist a bit more
readable for a human.
GitHub offers a .github meta folder to store things like
Pull Request or Issue templates.
We move this file into the meta folder to keep the root a bit cleaner
and only related to code and not to the VCS environment.