[Memcached] - Add support for Memcached storage.

[arqo123]

Speedgoose currently supports InMemory strategy and RedisStrategy. There is another popular storage with which we need to integrate - Memcached.

Technical details:
The way of working this strategy should follow other strategies in the catalog
https://github.com/arqo123/speedgoose/tree/master/src/cachingStrategies

So in short it will be more or less like:

1. Add new strategy class
2. Extend types
3. Add new strategy to wrapper https://github.com/arqo123/speedgoose/blob/master/src/wrapper.ts#L41

Acceptance criteria:
Should correctly implements and CommonCacheStrategyAbstract
Every method should behave similarly for ex. RedisStrategy.
Should be unit tested