provide a message to customer to add cnames in capten cli

[srikrishnabh1]

@jebjohns to provide the message

[jebjohns]

Before starting the app deployment, please ensure the following records are updated in DNS:

Hostname: app.example.com
Type: CNAME
Value: app.azurewebsites.net

sample
Hostname: grafana.capten.intelops.app
Type: CNAME
Value: traefik-092fa8459db46a5c.elb.us-west-2.amazonaws.com

Hostname: agent.capten.intelops.app
Type: CNAME
Value: traefik-092fa8459db46a5c.elb.us-west-2.amazonaws.com

capten.intelops.app - clustomer domain name