feature(proxy): support brotli compression

[sullis]

:pencil: Description

• add support for brotli compression

Context

This PR adds the brotli4j library.

Netty 4.x will automatically detect the presence of brotli4j.

When brotli4j is on the runtime classpath, Netty enables brotli compression.

If brotli4j is missing from the runtime classpath, Netty does not provide brotli compression.