Import win32/resolv.rb that is required on Windows

[nobu]

Fix #53.

Memo of Procedure

1. Cloned a new repository and filtered following files using git-filter-repo.

   ext/win32/resolv/extconf.rb
   ext/win32/resolv/resolv.c
   glob:ext/*/lib/win32/resolv*.rb
   .git-blame-ignore-revs
   ext/win32/lib/==>ext/win32/resolv/lib/
   

2. Reset .git-blame-ignore-revs to truncate unrelated commits in the filtered repository.

3. Cherry-picked from the filtered repository into ruby/resolv clone.

4. Rewrite the last hash in .git-blame-ignore-revs.

[hsbt]

👍

@nobu We need to update resolv.gemspec with spec.extensions for mswin platform.