feat: centralize provider collection

Would love some auto-discovery of providers,
and some automatic settings form generation.

core/App.gd

@@ -44,5 +44,26 @@ func start_poll(poll):
 	get_tree().current_scene.set_poll(poll)
 
 
+func get_providers() -> Array:
+	var registered_providers = [
+		'MajorityJudgmentTwitchChatProvider',
+		'MajorityJudgmentDemoProvider',
+	]
+	var providers = Array()
+	for registered_provider in registered_providers:
+		var enabled = Config.get_parameter(
+			"provider_%s_enabled" % registered_provider,
+			false  # default
+		)
+		if enabled:
+			var provider = load(
+				"res://addons/majority_judgment/providers/%s.gd"
+				%
+				registered_provider
+			).new()
+			providers.append(provider)
+	return providers
+
+
 func timer(duration:int) -> SceneTreeTimer:
 	return get_tree().create_timer(duration)