controller: site-conf.xsd: simplify boolean types
controller: site-conf.xsd: simplify boolean types

Simplifies the awkward SCIPIO boolean defs - there was no need for the
explicit ternary "" case or enumeration - the attribute should simply be
omitted in those cases (and no default or required set in the xsd).

This should make them easier to read in and outside Eclipse.
ilscipio/scipio-erp,ilscipio/scipio-erp,ilscipio/scipio-erp,ilscipio/scipio-erp,ilscipio/scipio-erp