Build art_Persistency_RootDB library

Identified art_Persistency_RootDB as low level module in art, i.e.
minimal internal dependencies (e.g "Core" is not strictly Core!)

Selectively recurse into the RootDB directory, and add relevant
build of library with links, interface specification and install.
Link interface does not completely match that specified by old
script. This needs testing on Mac to resolve possible dynamic lookup
issues.