Feature: make ap datatypes replacable with non-ap counterparts

[liss-h]

Add some kind of api to disable arbitrary precision datatypes for high performance requirements. Something like

DatatypeRegistry::disable_ap();

which replaces xsd:integer and xsd:decimal datatypes with non ap counterparts in the registry

[liss-h]

New info: probably will be a compile time flag, otherwise would result in lots of duplication or complexity

[liss-h]

An option to switch this is not planned, but we will switch to limited types in general