Support multiple valid header and query keys

[dnmh-psc]

Changed ApiKeyAuthenticationOptions to accept multiple allowed HeaderKeys and QueryKeys, so that multiple header and query keys can be valid.

If multiple valid query/header keys are added to a request, then each value for each valid key are validated as api key.

For example:

https://localhost:44362/TestApiKey?my-first-key=ABC&my-second-key=DEF

If both my-first-key and my-second-key are configured as valid keys (through ApiKeyAuthenticationOptions.QueryKeys), then both ABC and DEF are validated. The first valid API key is used to create a valid ClaimsPrinciple. If the first checked api key is not valid, then the next is checked before failing authentication.