Adds schema caching capabilities (5s by default) (#2286)

* Adds schema caching capabilities (off by default)

* Use InMemoryCacheAdapter

* Uses proper adapter to generate a cache

* Fix bugs when running disabled cache

* nits

* nits

* Use options object instead of boolean

* Imrpove concurrency of loadSchema

* Adds testing with SCHEMA_CACHE_ON

* Use CacheController instead of generator

- Makes caching SchemaCache use a generated prefix
- Makes clearing the SchemaCache clear only the cached schema keys
- Enable cache by default (ttl 5s)

src/Controllers/CacheController.js

@@ -13,9 +13,10 @@ function joinKeys(...keys) {
  * eg "Role" or "Session"
  */
 export class SubCache {
-  constructor(prefix, cacheController) {
+  constructor(prefix, cacheController, ttl) {
     this.prefix = prefix;
     this.cache = cacheController;
+    this.ttl = ttl;
   }
 
   get(key) {