farray.sh: REFACTOR: More flexible metadata retrieval. Using an array or alist variable name or token value (with prefix) is now supported in every function. This is possible because the value prefixes contain questin marks (?) which are not allowed in shell variable names. This again is a major precondition for recursive data structures (arrays/alists in arrays/alists).

syntax: regexp

^work-default/
^work-alldeps/
^docs/_build/
^docs/_venv.*/
^_venv.*/
^tests/fbhyve/bootvars.fd