* Provide basePath support
To be able to serve the application via a reverse proxy in a subfolder
smarty needs to be aware of the basepath if any.
* Provide basepath support via X-Forwarded headers
* Fix warnings
* Review adjustments
* Provide support X-Forwarded-Host header
* Use $uri in view factory directly
* Use middleware to set basepath from X-Forwarded-Path header
* Fix invalid type hint in RouterPathMiddleware
* Add "X-Forwarded-Host" to README
