Expand linting/styling QC (#28)

For my intended coming changes addressing #27, I wanted to make sure
tools for styling/linting md and toml files are available.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Documentation**
* README updated with an additional descriptive line about the catalog.

* **Chores**
* Reorganized project configuration to centralize style and lint
tooling.
* Consolidated build task formatting and simplified quality-check
command mappings.
* Added dedicated style and lint task groups covering Python, Markdown,
and TOML.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: jonasfreimuth

README.md

@@ -1,2 +1,3 @@
 # snakemake-plugin-catalog
+
 An automatically updated catalog of Snakemake plugins and their documentation