doc: Cleaner API docs, cleanup pipeline reference, faster rendering options, less noise in doc build output, changelog

[eddiebergman]

Note: Please feel free to ignore reviewing the actual content of the changes. I re-ordered the classes in components.py and so the diff looks a lot bigger then it is.

This PR focuses on:

1. Make the API documentation cleaner
   • No longer a right side TOC, gives more space to the content
   • TOC has labels to describe if it's a method, attr etc...
   • Attributes and functions are now seperated as cards with some small CSS. This gives them much more visible seperation.
     
2. The pipeline reference was not useful and merely dumped module docs. This was changed to be a more handcrafted reference. With that:
   • Removed the module doc of the components, it wasn't useful.
   • Removed mentions of the syntactic sugar. This was too much info and not something to advertise immediatly.
   • Made the __init__ actually display the parameters it takes, which previously was not there.
3. Rendering took a while as it would rerun all code blocks, even for a minor string change.
   • just docs now only renders the documentation and does not run code
     • A helpful message to use just docs-code to run and render code is placed in the code output
4. Loggers from SMAC and OpenML were polluting the documentation building output a lot when code was run. There are now hooks that disable this based on environment variables.
   • By default, the just docs commands will disable these log outputs
5. Added a change log tab
   

---

• I removed the custom templates used during generation of API. These provided little benefit and only forward compatibility worse.

• I added some documentation to the mkdocs.yml file as people investigating doc issues should look there first. This was also added to the CONTRIBUTING.md

[eddiebergman]

Merged but feel free to let me know if something here needs to be changed!