[instrumentation] Support setting image pull policy for agent images

[atoulme]

Component(s)

auto-instrumentation

Is your feature request related to a problem? Please describe.

The current setup relies on the default behavior of kubernetes imagePullPolicy as it is not set explicitly.

Describe the solution you'd like

Add a field to the instrumentation CRDs and config flags to support setting image pull policies globally or per instrumentation.

Describe alternatives you've considered

No response

Additional context

No response

[swiatekm]

👍 I'm in favor of adding this.