Convert FilterChain in Config into map of FilterChain

[XAMPPRocky]

With #698 and the ability to share cluster configuration between proxies, control planes, and relays, it might be worth also making filter chain configuration possible to contain multiple FilterChains at a given time that can be updated through a configuration provider, and allow the proxies to be configured to set their filter chain in the CLI.

As a bonus this would also allow for a filter that calls FilterChain which could be combined with other filters such as capture and match to allow you to dynamically switch filter chains.

[markmandel]

🤔 is this similar to the Match filter, but allowing to pass through data to a FilterChain, rather than just a single filter?

[XAMPPRocky]

is this similar to the Match filter, but allowing to pass through data to a FilterChain, rather than just a single filter?

There's two parts. The first is that our configuration schema moves from FilterChain to [(str, FilterChain)], this allows multiple filter chains to exist at the same time. This is important for the control planes and the relay because it would allow them to discover multiple filter chain definitions without overriding each other.

The second part is that leveraging that new schema we can also add filter that references a filter chain to execute it.

[markmandel]

That makes a lot of sense 👍🏻