Add support for SNI CRD

[saurabh-saraswat]

We can have CRD for SNI functionality of ATS.

It can be like ..
Informers watch the ATS-SNI CRD for create, update, and delete events and notify the controller. The controller then triggers the respective Add, Update, or Delete handler functions. These handler functions can modify sni.yaml and then trigger traffic_ctl config reload command.

[saurabh-saraswat]

We are going ahead with the implementation for following SNI CRD. Here we handle this one similar to Catching CRD, but from the handler we modify the sni.yaml followed by traffic_ctl server restart.

kind: ATSSniPolicy
metadata:
name: my-sni-config
spec:
sni:
- fqdn: "ats.test.com"
host_sni_policy: "PERMISSIVE"
verify_server_policy: "PERMISSIVE"
http2: "off"
verify_client: "MODERATE"
valid_tls_versions_in:
- "TLSv1_2"
- "TLSv1_3"
- fqdn: "host-test.com"
host_sni_policy: "ENFORCED"
verify_server_policy: "PERMISSIVE"
http2: "off"
verify_client: "MODERATE"
valid_tls_versions_in:
- "TLSv1_2"
- "TLSv1_3"