Support containerSecurityContext per deployment

[mjnagel]

Currently the only way to set container security context for the deployments is via anchoreGlobal.containerSecurityContext. While this is useful for a lot of things ("sane" default security) there are also cases where it falls short and you may want a more specific/locked down securityContext applied to a specific container, or more permissive applied to another.

Example deployment for reference: https://github.com/anchore/anchore-charts/blob/main/stable/anchore-engine/templates/api_deployment.yaml#L108-L111

What I would suggest we do is continue to allow for an anchoreGlobal value to set all container security contexts, but also allow (at minimum) a deployment specific option (i.e. anchoreApi.containerSecurityContext). This could easily be expanded if you want even more fine grained control over each container in a given deployment, but in my opinion a deployment wide setting should be sufficient for the "90%" use case.