Everyone get on the Visual Studio 2017 party train!

Updated Stratis.Bitcoin to version 1.0.1.5-alpha and removed NBitcoin, which is now replaced by NStratis

Replace Create/Recover and Load methods to use it.

Small API changes 

No such thing as a wrong password to recover a wallet. the recovered wallet will simply be a different one

Added utility endpoint for UI to list wallets files

* Add CORS service to allow Cross-Origin Requests

* Use CORS policy, add ubuntu runtime

- Use /wallet/files to see if the user has created a wallet on the default path (instead of /wallet/status)
- Change load function to POST
- Added login and logout functionality
- Enabled wallet loading
- Various small fixes

API specifications changed

- Handling HTTP status codes (temporary catching all statuses)
- Added default unit tests for all components
- Edited wallet load function
- Moved API error handling to components

Removed requirement for the client to provide a wallet folder path, as the default one will be used.