Support custom Compression/Decompressino

#### Describe the feature

We are using the older (Netty) version of the gRPC Server and implemented custom Snappy compression/decompression. We extended the (De)Compressor registry and registered it in the GrpcServer builder via

- compressorRegistry
- decompressorRegistry

I couldn't find any option to register custom (de)compressors in grpc-netty

#### Use cases

This feature is usefull when you need to compress the payload and don't want to use gzip because it's very heavy on CPU. I our case we decided to use Snappy because is comes with a nice balance between CPU usage and compression ratio

#### Contribution
I'm happy to implement this feature and it might be enough to just allow a custom Compressor/Decompressor Registry to be added to the GrpcServiceBridge and use them instead of the default registries to find the compressor needed.
But I'm not sure

Thanks you
Markus