Add logic for modules caching

Such files as cache-restore.ts, cache-utils.ts, constants.ts,
cache-save.ts we added. Main.ts file now incorporates logic for using
files mentioned above.

src/constants.ts

@@ -0,0 +1,8 @@
+export enum State {
+  CachePrimaryKey = 'CACHE_KEY',
+  CacheMatchedKey = 'CACHE_RESULT'
+}
+
+export enum Outputs {
+  CacheHit = 'cache-hit'
+}