Rework cache-warmup with CacheWarmer from Framework

[icanhazstring]

Regarding cache warming process: there is the CacheWarmer service in the framework itself, thanks to @TheCelavi. This service can be reused in bridges or by extending CacheWarmupCommand like in SF2 https://github.com/goaop/goaop-symfony-bundle/blob/master/Command/CacheWarmupCommand.php