Added nginx module

[Nashluffy]

This adds support for the nginx ingress controller. Similar to the Traefik support, and includes an nginx ingress dashboard.

The module assumes a few things about how nginx ingress is installed in your cluster...

• Prometheus metrics are being exported from the nginx controller on port 10254 which is the de-facto port. See here to expose metrics if installed via raw yaml, or here if installed via helm chart.
• All related resources are installed in the ingress-nginx namespace (default if following suggested installation)
• The module creates a service and exposes the prometheus port with a known name, which removes chance of name mismatch. It's not gonna mess anything up to have it defined twice, but may cause confusion if you aren't aware.

Here's a screenshot of what the dashboard looks like.

[Nashluffy]

Oops, I realize I accidentally committed a bunch of manifest files. Fixing now.

Edit: Fixed

[carlosedp]

This is very nice, thanks for the PR and the review!