Feature: add new supportive code for externalization of user-eval'd ACLs

In a nutshell, there two steps:

1. make internal-only information externalized as purposefully devised XML-level namespace captures ("annotations") for every element (and possibly attribute in the future) in the tree
   • see pcmk_acl_evaled_as_namespaces

2. make such annotations suitable for either machine or human friendly (for the latter, that presumes XML can be friendly as such, but there's hardly any friendlier _loseless_ presentation possible, especially once one is already accustomed to how CIB looks like) representation (totalling 4 = 2 + 2 kinds of outputs, which will be more comprehensible once the last mile in cibadmin is added...)

Also add some build-system related additions wrt. new file in a just
(as of previous commit) devised new subdivision on the "xml" root,
that is, the file that facilates all types of "output render" other
than "ns-full" (using the latter as its source).