Rename some files to avoid conflicting .obj files on Windows

BUILD

CMakeLists.txt

Makefile

build.yaml

src/cpp/client/channel_cc.cc

src/cpp/client/credentials_cc.cc

src/cpp/common/completion_queue_cc.cc

src/cpp/server/server_cc.cc

src/cpp/util/byte_buffer_cc.cc

src/cpp/util/slice_cc.cc

src/cpp/util/time_cc.cc

test/cpp/util/test_config_cc.cc

tools/doxygen/Doxyfile.c++.internal

tools/run_tests/sanity/check_sources_and_headers.py

tools/run_tests/sources_and_headers.json

vsprojects/vcxproj/grpc++/grpc++.vcxproj

vsprojects/vcxproj/grpc++/grpc++.vcxproj.filters

...cts/vcxproj/grpc++_test_config/grpc++_test_config.vcxproj

...roj/grpc++_test_config/grpc++_test_config.vcxproj.filters

vsprojects/vcxproj/grpc++_unsecure/grpc++_unsecure.vcxproj