Introduction of Github templates

[rartych]

Problem description
Github templates for issues and pull requests were configured for this repository.

Expected action
You can use it for new issues or open blank issue. Feel free to edit texts and proposed structure according to your needs.

Additional context
More info is included in Commonalities documentation.

[jpengar]

@rartych This issue has been already addressed in #19, hasn't it?

[hdamker]

@rartych maybe you want to convert this issue into an announcement within "discussions". (https://docs.github.com/en/discussions/managing-discussions-for-your-community/moderating-discussions#converting-an-issue-to-a-discussion)