ASP.NET Core middleware

[mausworks]

This PR adds a new project named "Pidget.AspNet", along with some test projects. Foremost, it includes an ExceptionReportingMiddleware which captures exceptions thrown by the invocation of the request delegate, appends data captured from the request and then sends it to Sentry using the DSN provided in the ExceptionReportingOptions.

Captured exception are then "silently" re-thrown, meaning a preceding middleware may be used to additionally handle thrown exceptions. It is intentionally written to not obfuscate the original exception thrown; just forward it.

The project also includes the dependency injection extensions ConfigurePidgetMiddleware, which are used to simplify configuration of the exception reporting middleware.

Sentry also strongly suggests sanitizing request data on the client-side so support for this has been added and can be configured through the SanitationOptions property on the ExceptionReportingMiddleware.

TODO:

• README / documentation.
• Include headers in event
• Include cookie in event
• Include form data in event (currently only "application/x-www-form-urlencoded" is supported)
• Include JSON body data in event (upcoming feature)
• Header sanitizing
• Query string sanitizing
• Cookie sanitizing
• Form data sanitizing
• Deep JSON sanitizing (upcoming feature).