Refine to use the same template as in other JabRef repos

[InAnYan]

To prepare for publishing

[palukku]

Did some refactoring in #11, is this sufficient or should it say more?

When we have a published version we also add the links etc. ofc

[koppor]

I commented on the PR; the lower README contents could be split into issues and CONTRIBUTING.md.

[InAnYan]

UPD: Made this issue bigger. This would include:

• README
• CONTRIBUTING
• MAINTAINERS
• maybe connectign assign-me
• docs
• ADRs
• Add badges to README

IDK, maybe it would be better to make smaller specific issues?