[graphite] add pod security policy

[davidphay]

What this PR does / why we need it:

Add pod security policy support

Which issue this PR fixes

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)

• fixes #

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] DCO signed
• [x] Chart Version bumped (if the pr is an update to an existing chart)
• [x] Variables are documented in the README.md
• [x] Title of the PR starts with chart name (e.g. [fluentd-elasticsearch])

[davidphay]

@monotek Hello can you take a look please ?

[davidphay]

@rpahli Hello I rebase the branch it should be good now.

[davidphay]

@rpahli It should be good now