Update to compatibility with Big Bang v1.14.1

What/Why

⚠ BREAKING CHANGES ⚠

Update module for compatibility with Big Bang v1.14.1. This module will NOT be backwards compatible with v1.12.0 due to changes listed below:

• The Flux k8s manifests got a big upgrade
• get-eip.sh looks for a service called public-ingressgateway now instead of istio-ingressgateway since that's what 1.14.1 creates

Also deprecated the variable reduce_flux_resources since the new Flux manifest already has much smaller requests than limits. The old flux.yaml had the limits and requests set as the same values, which puts the service in "guaranteed" mode, but the new Flux manifest from the Big Bang repo doesn't do that.

Changes validated in the Big Bang Quickstart repo in this Merge Request

Fixes #4 (closed)