added firebase and rudimentary leaderboard support

addons/godot-firebase/auth/auth_provider.gd

@@ -0,0 +1,32 @@
+@tool
+class_name AuthProvider
+extends RefCounted
+
+var redirect_uri: String = ""
+var access_token_uri: String = ""
+var provider_id: String = ""
+var params: Dictionary = {
+    client_id = "",
+    scope = "",
+    response_type = "",
+    state = "",
+    redirect_type = "redirect_uri",
+}
+var client_secret: String = ""
+var should_exchange: bool = false
+
+
+func set_client_id(client_id: String) -> void:
+    self.params.client_id = client_id
+
+func set_client_secret(client_secret: String) -> void:
+    self.client_secret = client_secret
+
+func get_client_id() -> String:
+    return self.params.client_id
+
+func get_client_secret() -> String:
+    return self.client_secret
+
+func get_oauth_params() -> String:
+    return ""