Update header matcher to use v3 string_match api

[jacob-delgado]

Fixes #5649

Envoy v3 api introduced the string_match api for HeaderMatcher. See envoyproxy/envoy#9694

The former api is deprecated, but has not been removed. Add support for it.

Due to a unit test setting up a proxyless XDS server I am not able to merge in istio/istio#40886 as I get the following error.

2022-09-09T00:05:31.979790Z	info	[xds] [xds-server-listener 0xc001003c00] Received error for resource "xds.istio.io/grpc/lds/inbound/[::]:46069": network filters {[]} had invalid server side HTTP Filters {[name:"envoy.filters.http.rbac.DENY"  typed_config:{[type.googleapis.com/envoy.extensions.filters.http.rbac.v3.RBAC]:{rules:{action:DENY  policies:{key:"test-echo-rbac-mtls-0"  value:{permissions:{and_rules:{rules:{any:true}}}  principals:{and_ids:{ids:{or_ids:{ids:{header:{name:"echo"  string_match:{exact:"block"}}}}}}}}}}}} name:"envoy.filters.http.rbac"  typed_config:{[type.googleapis.com/envoy.extensions.filters.http.rbac.v3.RBAC]:{rules:{policies:{key:"test-echo-rbac-mtls-allow-0"  value:{permissions:{and_rules:{rules:{any:true}}}  principals:{and_ids:{ids:{or_ids:{ids:{header:{name:"echo"  string_match:{exact:"allow"}}}}}}}}}}}} name:"envoy.filters.http.router"  typed_config:{[type.googleapis.com/envoy.extensions.filters.http.router.v3.Router]:{}}]}: error parsing config for filter "type.googleapis.com/envoy.extensions.filters.http.rbac.v3.RBAC": rbac: error constructing matching engine: unknown header matcher type, xDS client nodeID: sidecar~127.0.1.1~echo-rbac-mtls.test~test.svc.cluster.local

RELEASE NOTES:

• Support the string_match api in HeaderMatcher for xds grpc.

[linux-foundation-easycla]

• ❌ - login: @jacob-delgado . The commit (72e4144) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[easwars]

@jacob-delgado : Could you please sign the CLA before we start reviewing the PR. Thanks.

[zasweq]

Hello, thank you so much for the PR :D. This is something we want, however we want a gRFC first to officially document this so it can be kept consistent across different gRPC languages. Until then, I will go ahead and close this, and when the gRFC comes out, we can go ahead and review this.