Split ADA / Databricks section into two subsections

[jen-machin]

Is your feature request related to a problem? Please describe.
I think that people are going to either want to read about the context of Databricks OR follow a guide to tell them how to do something

Describe the solution you'd like
Two subsections (open to change for the name of the subsections, but roughly along these lines):

• How Databricks works
• How-to guides (e.g. set up Databricks to connect to RStudio, set up Databricks to connect to Git)

Describe alternatives you've considered
Keeping it all in one section, but we're going to end up with a lot of overlap / duplication and this might help to resolve that