docs: adds the initial documentation site

[claymcleod]

I wanted to add a few sentences describing the philosophy and goals that led to the creation of Sprocket. Though everything on the page may not be true (yet) today, it will be a good goal-post to work towards while providing the community some sense of where we are going.

Before submitting this PR, please make sure:

• You have added a few sentences describing the PR here.
• You have added yourself or the appropriate individual as the assignee.
• You have added at least one relevant code reviewer to the PR.
• Your code builds clean without any errors or warnings.
• You have added tests (when appropriate).
• You have updated the README or other documentation to account for these changes (when appropriate).