http: new filter chain filter

[wbpcode]

Commit Message: http: new filter chain filter
Additional Description:

• New filter to configured multiple sub filter chains and allow the route to select one or provide a inline sub filter chain.

This PR gives the actual per route level filter chain support. We only need to ensure most filters could support the createFilterFactoryFromProtoWithServerContext.

This filter is a little similar to composite, but with following difference:

• provides full feature sub filter chain support.
• not as flexible as composite filter, only the initial route could be used to help to select the sub filter chain, but more easier to use and more robust for lots scenarios.

Risk Level: low. new filter.
Testing: unit/integration.
Docs Changes: added.
Release Notes: added.
Platform Specific Features: n/a.

[repokitteh-read-only]

CC @envoyproxy/api-shepherds: Your approval is needed for changes made to (api/envoy/|docs/root/api-docs/).
envoyproxy/api-shepherds assignee is @adisuissa
CC @envoyproxy/api-watchers: FYI only for changes made to (api/envoy/|docs/root/api-docs/).

🐱

Caused by: #42912 was opened by wbpcode.

see: more, trace.

[wbpcode]

I like it, CI are all green.