Adds Counters and Lists to CSharp SDK (#3581)

* Adds Counter methods to CSharp SDK
* Adds Lists methods to Csharp SDK
* Adds csharp client SDK documentation for counts and lists
* Adds feature publication gate for the csharp SDK to the Agones docs
* Formatting fixes for the C# SDK documentation.

This also includes some fixes for PlayerTracking, so it's all formatted
consistently.

---------

Co-authored-by: Mark Mandel <markmandel@google.com>

build/includes/sdk.mk

@@ -187,7 +187,7 @@ run-sdk-conformance-test-csharp:
 	# run without feature flags
 	$(MAKE) run-sdk-conformance-test SDK_FOLDER=csharp GRPC_PORT=9005 HTTP_PORT=9105
 	# run with feature flags enabled
-	$(MAKE) run-sdk-conformance-test SDK_FOLDER=csharp GRPC_PORT=9005 HTTP_PORT=9105 FEATURE_GATES=PlayerTracking=true TESTS=$(DEFAULT_CONFORMANCE_TESTS),$(ALPHA_CONFORMANCE_TESTS)
+	$(MAKE) run-sdk-conformance-test SDK_FOLDER=csharp GRPC_PORT=9005 HTTP_PORT=9105 FEATURE_GATES=$(ALPHA_FEATURE_GATES) TESTS=$(DEFAULT_CONFORMANCE_TESTS),$(ALPHA_CONFORMANCE_TESTS),$(COUNTS_AND_LISTS_TESTS)
 
 run-sdk-conformance-test-rest:
 	# (note: the restapi folder doesn't use GRPC_PORT but run-sdk-conformance-no-build defaults it, so we supply a unique value here)