create zalenium helm chart into incubator

[hoatle]

from our current best practices and styles

[hoatle]

depends on #10 #1

[hoatle]

@hoavt make sure to review the content and verify the content by following the docs to run.

[hoavt]

1/ change $ helm install --name example-name
--set rbac.create=false
teracy-incubator/zelenium --> $ helm install --name example-name
--set rbac.create=false
teracy-incubator/zalenium

2/ Need to refer to the doc "add repo" https://github.com/teracyhq/helm-charts/blob/master/README.md#how-do-i-enable-the-incubator-repository
before the step "Installing the chart"

[hoavt]

3/ Cannot access zalenium grid hub

[hoatle]

we're not going to create the helm chart for zalenium but use the official helm chart instead, so we need doc to be moved to the teracy-dev-k8s project.

[hoatle]

and delete the zalenium helm chart from this repo.