contrib/envoyproxy: envoy external processing support #3281

Job	Run time
Prepare Go modules cache	11s
Smoke Tests	0s
macos-12 go1.23	6m 27s
macos-12 go1.22	5m 54s
macos-latest (AppSec disabled)	2m 9s
macos-14 go1.23	3m 5s
windows-latest (AppSec disabled)	3m 7s
macos-14 go1.22	4m 29s
ubuntu-latest-16-cores (AppSec disabled)	1m 11s
linux/amd64 golang:1.23-bookworm	1m 21s
linux/arm64 golang:1.23-bookworm	3m 9s
linux/amd64 golang:1.23-bullseye	1m 42s
linux/arm64 golang:1.23-bullseye	3m 7s
linux/amd64 golang:1.23-alpine	1m 32s
linux/arm64 golang:1.23-alpine	2m 58s
linux/amd64 golang:1.22-bookworm	1m 33s
linux/arm64 golang:1.22-bookworm	3m 14s
linux/amd64 golang:1.22-bullseye	1m 25s
linux/arm64 golang:1.22-bullseye	3m 1s
linux/amd64 golang:1.22-alpine	1m 21s
linux/arm64 golang:1.22-alpine	3m 0s
	53m 56s

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