script: add base class for serializing core structures for scripts
script: use CScriptBinaryData for all core structures that are added to scripts
script: remove old methods of writing core structures
script: move ToString and ValueString out of the header
script: add a slew of includes all around before removing some from script.h

Lots of files ended up with indirect includes from script.h.
script: drop core includes

The string processing headers are sticking around for now, we may drop them
later.