gnu: guile-reader: Switch to Guile 3.0.

* gnu/packages/guile-xyz.scm (guile-reader)[inputs]: Switch to GUILE-3.0.
(guile2.2-reader): New variable.
* gnu/packages/guile-xyz.scm (haunt)[propagated-inputs]: Add GUILE-READER.
(guile2.2-haunt)[propagated-inputs]: Use GUILE2.2-READER.
* gnu/packages/skribilo.scm (skribilo)[propagated-inputs]: Use
GUILE2.2-READER and GUILE2.2-LIB.