Integration tests project (#2083)

Move integration tests into their own project. This makes it easier to run unit tests if you don't want to (or don't have) `azurite` running, since you can `dotnet test` just that directory.

Also add a check into the `AzuriteStorage` class that will abort the entire test run if `azurite` is not running, which is simpler than reading lots of socket exceptions.

src/ApiService/IntegrationTests/Fakes/TestUserCredentials.cs

@@ -0,0 +1,19 @@
+using System.Threading.Tasks;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.OneFuzz.Service;
+
+using Async = System.Threading.Tasks;
+
+namespace IntegrationTests.Fakes;
+
+sealed class TestUserCredentials : UserCredentials {
+
+    private readonly OneFuzzResult<UserInfo> _tokenResult;
+
+    public TestUserCredentials(ILogTracer log, IConfigOperations instanceConfig, OneFuzzResult<UserInfo> tokenResult)
+        : base(log, instanceConfig) {
+        _tokenResult = tokenResult;
+    }
+
+    public override Task<OneFuzzResult<UserInfo>> ParseJwtToken(HttpRequestData req) => Async.Task.FromResult(_tokenResult);
+}