docs release v1.7.16

Added caveat for IC installation on AWS (#454) Replacement of Happa with Web UI (#453) Change default keypair/kubeconfig TTL to 1 day (#456) Update app catalog basic guide image and urls. (#457) Light editing and a closing sentence (#459) Spelling and readability (#460) Edited for typos and English (#458) Name Change: App Catalog to App Platform (#440) Removal of references to K8s 1.9 (#455) Typos and readability (#461)