Create an analyzer to detect mismatched parameter optionality

[captainsafia]

As a follow-up to the work completed in #34505, we should add support for labeling optional parameters in a route using the route string. For example:

app.MapGet("/action/{foo?}", (string? foo) => ...)

Will treat the foo parameter as optional in the endpoint above. For scenarios where the optionality defined in the route and the optionality defined in the method differ, then we will throw an exception. For example, the route string below defines a parameter as optional but the method defines it as required:

app.MapGet("/action/{foo?}", (string foo) => ...);

This feature can be achieved by examining the values of factoryContext.RouteParameterNames and factoring it into the data binding done in BindParametersFromQueryOrRouteValue.

[captainsafia]

Note: as part of this we should also validate how this behaves in swagger. See more info at https://gist.github.com/rafikiassumaniMSFT/52f9a6f9d005a38b668315d4f7db262b#gistcomment-3840821

[captainsafia]

Following a recent discussion, we've decided that for this issue, we are going to focus on writing a set of analyzers to alert users about problematic scenarios. The analyzer + codefix will instruct users to add the optionality flag to the arguments in addition to the route param.