Fix minimal and old_interpreter MeTTa incompatibilities

[vsbogd]

Rename apply to atom-subst in order to make name more unique and better reflect nature of the function. Fix case of passing Error expressions as a function parameters. In particular:

! (get-type Error) ; (-> Atom Atom ErrorType)
! (get-metatype Error) ; Symbol
! (get-type (Error Foo Boo)) ; ErrorType
! (Error (+ 1 2) (+ 1 +)) ; (Error (+ 1 2) (+ 1 +))