correctly delete value cache
add Kwf_Cache_SimpleStatic and use it where appropriate

using that we can implement two types of caches: one that can
get deleted and should be shared across server instances and
one that is static and will only get deleted on clear-cache
Cache_Simple: add support for Aws ElastiCache
SimpleCache: add namespace to invalidate cache when using Aws ElastiCache
add own cache for view cache in memory

will not get deleted when doing a clear-cache
add hashPrivatePart setting to share salt across multiple web servers
move clearing apc cache debug output into Util_Apc

code gets simpler that way and it's possible to add features there
output not-domain-set error
ClearCache: support multiple aws ec2 servers when deleting apc cache
add apcUtilsPass to config to have same password on all servers
add exception to prevent counters getting wrongfully used
ClearCache: remove unused code and server option
add smtp config to use smtp transport by default when sending mail using Kwf_Mail
use Kwf_Cache_SimpleStatic
clear filesystem caches on other servers thru ssh
remove todo as this is not true

lifetime is resprected thru the lifetime of the media-output cache
remove deleting cache/media file, the file will be regenerated if media-output is deleted
don't clear-cache for ourself
refactor getting other ec2 instances into resuable method
write maintenance bootstrap on all aws hosts