chore: add JSON-Schema-Test-Suite

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "thirdparty/JSON-Schema-Test-Suite"]
+	path = thirdparty/JSON-Schema-Test-Suite
+	url = git@github.com:json-schema-org/JSON-Schema-Test-Suite.git

thirdparty/JSON-Schema-Test-Suite

@@ -0,0 +1 @@
+Subproject commit 8ef15501fa68155dcae3ec2431492dae5039a02a