fix(caching): properly respect ttl for all cache levels

ts/levelcache.abstract.classes.cache.ts

@@ -4,22 +4,35 @@ export abstract class AbstractCache {
   public abstract ready: Promise<void>;
   public abstract status: 'active' | 'inactive';
 
-  // Blobs
+  // Cache Entries
   /**
    * store a Blob
    */
   public abstract storeCacheEntryByKey(keyArg: string, valueArg: CacheEntry): Promise<void>;
 
-  // Cache Entries
   /**
    * retrieve cache entry
    */
   public abstract retrieveCacheEntryByKey(keyArg: string): Promise<CacheEntry>;
 
+  /**
+   * checks for the presence of a key
+   * @param keyArg
+   */
   public abstract checkKeyPresence(keyArg: string): Promise<boolean>;
 
   /**
-   * cleans the cache
+   * delete a key
    */
-  public abstract clean(): Promise<void>;
+   public abstract deleteCacheEntryByKey(keyArg: string): Promise<void>;
+
+  /**
+   * clean the cache
+   */
+  public abstract cleanOutdated(): Promise<void>;
+
+  /**
+   * cleans the complete cache
+   */
+  public abstract cleanAll(): Promise<void>;
 }