Add static content (pdfs and assessments) next to old security review

[theopolis]

I know we have at least one other assessment to add.

[terracatta]

@theopolis what are the links to the assessments?

[theopolis]

https://github.com/facebook/osquery/tree/master/docs/static/docs https://github.com/facebook/osquery/tree/master/docs/img

These are the two paths to static content that I see others linking to