Host website in IIS via OWIN and F#

NOT READY TO MERGE

## To-Do
- [x] create an F# library for the QED OWIN confguration to be shared between a website and qed.exe
- [x] create an F# ASP.NET website that hosts OWIN and QED
- [ ] move the middlewares (dispatcher, method override, mustache, content type) to the OWIN library
- [ ] move the request handlers to the OWIN library
- [ ] move the OWIN extensions into the OWIN library
- [ ] make hosting the website via qed.exe optional (and off by default)