Nuke unused files

BUILD

Makefile

binding.gyp

build.yaml

gRPC.podspec

src/core/client_config/resolvers/dns_resolver.c

...nt_config/subchannel_factory_decorators/add_channel_arg.c

...nt_config/subchannel_factory_decorators/add_channel_arg.h

...config/subchannel_factory_decorators/merge_channel_args.c

...config/subchannel_factory_decorators/merge_channel_args.h

tools/doxygen/Doxyfile.core.internal

tools/run_tests/sources_and_headers.json

vsprojects/vcxproj/grpc/grpc.vcxproj

vsprojects/vcxproj/grpc/grpc.vcxproj.filters

vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj

...jects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters