refactor: Speed up Config fetching and Setup Config Groundwork 👷🚧 (#1297)

* refactor: move endpoint services to own directory

* refactor: make endpointconfig handling more concise, separate logic, and cache result for subsequent serving

* refactor: ModelController gets same treatment as EndpointController, draft OverrideController

* wip: flesh out override controller more to return real value

* refactor: client/api changes in anticipation of override

api/server/services/Config/index.js

@@ -0,0 +1,13 @@
+const { config } = require('./EndpointService');
+const loadDefaultModels = require('./loadDefaultModels');
+const loadOverrideConfig = require('./loadOverrideConfig');
+const loadAsyncEndpoints = require('./loadAsyncEndpoints');
+const loadDefaultEndpointsConfig = require('./loadDefaultEConfig');
+
+module.exports = {
+  config,
+  loadDefaultModels,
+  loadOverrideConfig,
+  loadAsyncEndpoints,
+  loadDefaultEndpointsConfig,
+};