feat: Add possibility to configure key prefix (Redis, MemCached)

[AJIOB]

• Add possibility to configure key prefix for Redis & MemCached
• Unify Redis & MemCached expiraction time
• Actualize configuration docs

[codecov-commenter]

Codecov Report

Attention: 38 lines in your changes are missing coverage. Please review.

Comparison is base (ffe3070) 30.77% compared to head (2131617) 30.70%.

Files	Patch %	Lines
src/config.rs	15.62%	18 Missing and 9 partials :warning:
src/cache/cache.rs	0.00%	6 Missing :warning:
src/cache/memcached.rs	0.00%	3 Missing :warning:
src/cache/redis.rs	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2084 +/- ## ========================================== - Coverage 30.77% 30.70% -0.08% ========================================== Files 52 52 Lines 19913 19944 +31 Branches 9630 9658 +28 ========================================== - Hits 6129 6123 -6 - Misses 7959 7990 +31 - Partials 5825 5831 +6 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[sylvestre]

if i understand correctly this PR, it isn't going to change the behavior of existing configurations, right?

[AJIOB]

@sylvestre, yes, you are right.

I am not changed the current configuration API. Just documenting, unifying & extending it.

[AJIOB]

@Xuanwo, hello.

What I need to do for merging this PR?

Do we have some problems with this changes? Or I need to split it to few ones?

[Xuanwo]

Those changes LGTM! cc @sylvestre do you want to take another look?

[sylvestre]

thanks!