Added logo, bandages and more

Added owlapy logo in README.md and on documentation sidebar.
Added static bandages on top of README.md leading to coverage report, pypi and docs.
Added further_resources.md on docs. It has some additional genera information and the coverage report.
Coverage report generation also added in .github workflow.
Added favicon for documentation (descided to go with a little book icon frequently used on docs pages).

_Image resources placed at the following folder: docs/_static/images_

dice-group / owlapy