Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/387978

**Problem**

Sometimes we provide a `ProjectPresenter` object to the CacheService.
Because we use `object.class.name` for the Redis key generation, it
leads to duplicated keys problem when Project and ProjectPresenter
objects generate different keys.

**Solution**

* Extract CacheKey generation logic into a separate class
* Use `is_a?` (via case statement) to identify object type

Changelog: performance