Configuration templates

Currently there is a 1:1 relationship between configuration and named caches. While the programmatic API does have the ability to .read() an existing configuration to create a new one, the declarative config does not.
We should introduce the concept of configuration inheritance, e.g.:

<local-cache name="eviction-cache">
    <eviction strategy="LIRS" maxEntries="10000"/>
</local-cache>

<local-cache name="mycache" template="eviction-cache" />

Possibly, cache templates should be made "abstract" so that they cannot be instantiated as named caches directly, e.g.:

<local-cache name="eviction-cache" abstract="true">
...
</local-cache>