gRPC is currently getting formatted with two different clang-format implementations, and due to some weirdness they have different include file orderings. This change introduces clang-format configuration to ensure that the two systems align - it's *highly* expected that this will need some maintenance going forward as the two systems evolve.
Closes#40905
PiperOrigin-RevId: 819606209
As Protobuf is going to support Cord to reduce memory copy when
[de]serializing Cord fields, gRPC is going to leverage it. This
implementation is based on the internal one but it's slightly modified
to use the public APIs of Cord. only
