Allow specifying compression encoding order preference

[CapCap]

Motivation

Although Zstd is significantly more performant (> 5x in our testing), the default chosen encoding remains Gzip when both are enabled. This blocks us from being able to gradually roll out zstd support for existing downstream clients before disabling Gzip entirely.

Solution

This PR introduces a feature that allows for specifying the order of compression encodings. The key changes include:

• Updated EnabledCompressionEncodings to support ordering/prioritizing multiple compression encodings such as Gzip and Zstd.
• Modified the enable function to reorder encodings based on the priority, ensuring the most recently enabled encoding has the lowest priority- i.e "first encoding enabled has the highest priority"
• Added new tests to validate the correct priority ordering of compression encodings settings.
• Make sure GRPC correctly copies this order for each connection as well.

The behavior is now "given a list of supported encodings, I will pick the highest priority one that I support"

[LucioFranco]

@CapCap I ran CI looks like there are some failures, can you address those and then ping me again when its ready for review and CI is passing? thanks

[djc]

@CapCap we merged #1757 which is substantially similar to this -- hope that's okay and that it address your issues. If not, please open an issue so we can discuss in more detail what you need.