Add a method to clear entire cache except a few keys

[cheap-glitch]

It could be named something like cache.clearExcept, and would accept an array of keys to preserve.

This would allow resetting the cache easily while keeping some important data, e.g. login credentials.

[fregante]

There's actually an internal method that does this and it's being called by clear. Basically we just need to use export const clear = deleteWithLogic and it will work right away. PR welcome