Update SSL Redirect Status Code to 308

[danehans]

When GW API releases with kubernetes-sigs/gateway-api#3823, do the following:

1. Bump to the release (including kgtw)
2. Update docs.
3. Update emitter (pkg/i2gw/implementations/kgateway/ssl_redirect.go).
4. Update integration/e2e tests.

[danehans]

Note: The emitter code path changes when #45 is merged.