This will fix #9989, #11603, #11751.
no_proxy is typically comma separated list of hosts and or domains. Matching must be from the end of the uri to accomodate whole domain and subdomain whitelisting.

This will work for well-formed no_proxy strings, but may fail if there are additional spaces.

require using grpc_slice

"proto" and "*.egg-info/" are no longer generated, "src/" can be
narrowed to "/src/", and "*_pb2.py" and "*_pb2_grpc.py" are covered by
.gitignore files in parent directories.

- In C++, we need a constant for the max lifetime.
- In C, make sure that we crop the lifetime in the credentials object
itself and not just later during the creation of the token. This will
allow the refresh to occur based on the actual token lifetime as opposed
to the one from the user (which may be cropped).