Web UI mainly uses declarative way of defining UI structure. When a new object type is created it is often required to create a new builder which would build the objects from spec file. The builders' logic is mostly the same. This patch adds a general builder with some extendability capabilities.
Now it is possible to:
1) define spec for single object and build it by calling IPA.build(spec, /* optional */ builder_fac)
2) define an array of specs and build the objects by the same call
Prerequisite for following action list patches.
https://fedorahosted.org/freeipa/ticket/2707
12401fe4da
