* add extension method to rewrite requests meant for backoffice static assets
* add backoffice rewrites to application builder
* embed the umbraco hash into the static assets requested on the backoffice
* Added a IStaticFileHostGenerator so its possible to replace our logic
* add docs and ensure the path is uniform with single slashes
---------
Co-authored-by: Bjarke Berg <mail@bergmania.dk>
ddca33337b