website/docs: add content about bindings #25339

Job	Run time
lint-golint	1m 20s
test-unittest	3m 9s
ci-outpost-mark	1s
build-container (proxy)	2m 22s
build-binary (proxy, linux, amd64)	1m 21s
build-container (ldap)	2m 16s
build-binary (proxy, linux, arm64)	1m 42s
build-binary (ldap, linux, amd64)	1m 13s
build-container (radius)	2m 17s
build-container (rac)	2m 16s
build-binary (ldap, linux, arm64)	1m 38s
build-binary (radius, linux, amd64)	1m 14s
build-binary (radius, linux, arm64)	1m 38s
build-binary (rac, linux, amd64)	1m 11s
build-binary (rac, linux, arm64)	1m 45s
	25m 23s

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