Resurrect Envoy on Windows

Big thanks to @anuraaga for keeping Windows Envoy fork.

Open tasks:

The top most commit in the envoyproxy/envoy-windows repo contains a patch needed to build Envoy on Windows and bazel command line.

To build Envoy: `bazel --bazelrc=bazelrc.windows build -c fastbuild --config=windows //:envoy`
Tests: `bazel --bazelrc=bazelrc.windows test -c fastbuild --config=windows //test/...`

Please add your name next to the item you are working on.

- [ ] Fix Windows build post bzlmod migration
- [x] Create envoyproxy/envoy-windows repo
- [ ] Create GH action to rebase envoyproxy/envoy-windows on envoyproxy/envoy every N minutes
- [ ] Create docker image with build tools.
- [ ] Create GH actions to use Google RBE for building Envoy on Windows in envoyproxy/envoy-windows
- [x] Create bazelrc.windows with windows build settings #46845
- [x] Unit test link fails because Windows linker wants all exported symbols to be defined (unlike GNU ld, which ignores undefined symbols). Causes undefined symbol errors for all exported dyn modules symbols. (#47099)
- [ ] Fix bit rotted unit tests
- [ ] Move small changes from the patch to Envoy repo.
- [ ] Cleanup the reverse tunnel patch -< @hjk068 (#47062)
- [ ] Implement dynamic modules Windows platform code. Preferrable to use Windows native calls instead of dlwin wrapper which needs additional tweaks in the barebones toolchain.
- [ ] optional: publish artifacts. Maybe docker image with Envoy?

For reference:
https://github.com/curioswitch/py-envoy-server/blob/main/.github/actions/build-windows/action.yaml#L35