Add Styling.md

[digitaldirk]

New document to help guide users on what can be configured style wise (colors, fonts,...) and where in code to find/edit them.

I was thinking to include the current fonts/README.md into this new document.

Also having an image example of config settings like BlogBrandUrl from Setup/Configuration.md would also be helpful for users to visualize the difference between having and image and BlogName.

[linkdotnet]

That might be a good idea - probably also revisiting if we can put some more styling options out in the config. Kind of having like "Themes". But that would be a step 2