contrib/envoyproxy: envoy external processing support #3278

Job	Run time
Prepare Go modules cache	46s
Smoke Tests	0s
macos-12 go1.23	8m 45s
macos-latest (AppSec disabled)	2m 48s
macos-12 go1.22	6m 11s
linux/amd64 golang:1.23-bookworm	1m 30s
windows-latest (AppSec disabled)	3m 28s
macos-14 go1.23	3m 14s
linux/arm64 golang:1.23-bookworm	3m 6s
ubuntu-latest-16-cores (AppSec disabled)	1m 24s
macos-14 go1.22	3m 42s
linux/amd64 golang:1.23-bullseye	1m 29s
linux/arm64 golang:1.23-bullseye	3m 6s
linux/amd64 golang:1.23-alpine	1m 17s
linux/arm64 golang:1.23-alpine	2m 59s
linux/amd64 golang:1.22-bookworm	1m 24s
linux/arm64 golang:1.22-bookworm	3m 10s
linux/amd64 golang:1.22-bullseye	1m 21s
linux/arm64 golang:1.22-bullseye	3m 0s
linux/amd64 golang:1.22-alpine	1m 20s
linux/arm64 golang:1.22-alpine	2m 56s
	56m 56s

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