Fix publish-service patch and update README

[victortrac]

What this PR does / why we need it: deploy/patch-deployment.yaml is a JSON patch that replaces the args created by deploy/with-rbac.yaml or deploy/without-rbac.yaml. This means the args have to be updated 3 times if anything changes.

This is changes the patch to actually do an add operation for the providers that require the --publish-service argument (e.g. https://github.com/kubernetes/ingress-nginx/tree/master/deploy#aws). It also formats the JSON to be a bit more readable instead of a single line.

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[k8s-reviewable]

This change is 

[coveralls]

Coverage remained the same at 36.764% when pulling 918da87 on victortrac:master into cabd7cb on kubernetes:master.

[coveralls]

Coverage remained the same at 36.764% when pulling 918da87 on victortrac:master into cabd7cb on kubernetes:master.

[aledbf]

/lgtm

[aledbf]

@victortrac thanks!