ConfigurableDataResource_impl/ConfigurableDataResourceSpecifier requires additional work

ConfigurableDataResource_impl appears to be stuck in a half-living state:

• there is no ConfigurableDataResource interface (UIMA usually has interfaces for such things)
• there is no factory method in the ResourceSpecifierFactory for a ConfigurableDataResourceSpecifier
• the "local cache" facility has never been implemented, there is only an unused "getLocalCache()" method

A good thing about the ConfigurableDataResourceSpecifier, though, is that it supports ResourceMetaData and the regular UIMA parameters (cf. UIMA-2978). Maybe it would be useful to pull up the ResourceMetaData support into the ResourceSpecifier.

uimaFIT uses the ConfigurableDataResourceSpecifier whenever an external resource is declared in conjunction with a SharedResourceObject.