Update Windows-specific documentation

Update Windows-specific documentation

Bring the files describing Windows-specific aspects of building and
installing BIND up to date.  Remove the parts which are either outdated
(e.g. 32-bit build instructions), already included elsewhere (e.g. the
list of Windows systems BIND is known to run on), or inconvenient to
keep up to date in the long run (e.g. ARM chapter numbers).