add NET_BROADCAST to allowedCaapbilities section

[gml3ff]

What does this PR do?

Existing SCC does not include the NET_BROADCAST capability which is required if you want to use NPM on OpenShift. If this capability is not added, the agent will not deploy at all. See example from a local deployment where I used the Operator:

Without NET_BROADCAST

[morgan.lupton@COMP10906:~/repos/operator-example-with-everything/manifests] (master)$ oc get pods 
NAME                                     READY   STATUS    RESTARTS   AGE
datadog-cluster-agent-64d774fc8d-9mzqs   1/1     Running   0          8m9s

With NET_BROADCAST

[morgan.lupton@COMP10906:~/repos/operator-example-with-everything/manifests] (master)$ oc get pods
NAME                                     READY   STATUS    RESTARTS   AGE
datadog-agent-zvrdd                      4/4     Running   0          20m
datadog-cluster-agent-64d774fc8d-9mzqs   1/1     Running   0          28m

Screenshot of working NPM configuration: https://a.cl.ly/yAub52qg

Motivation

What inspired you to submit this pull request?

Additional Notes

Anything else we should know when reviewing?

Describe your test plan

Write there any instructions and details you may have to test your PR.

[bits-bot]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[gml3ff]

@clamoriniere Do I need to do anything as far as adding milestones, release notes, and team labels? Looks like those are failing the CircleCI tests.