[RedisCache] Add staleTTL option to normal get and set

[rohit-gohri]

staleTTL is only an option for getOrSet. Should also be available to set function

[hit12369]

staleTTL is only an option for getOrSet. Should also be available to set function

Why is staleTTL needed in set and get?

get: Doesn't need it because the whole purpose of staleTTL is to generate value in background, if we don't have a set, having stateTTL is not gonna help.
set: staleTTL is not actually saved anywhere and checked by checking the createdAt of the value, so values created by set can be used with staleTTL in getOrSet.

Maybe I'm missing some scenario, an example is needed in that case.