Allow users to submit custom patches to nginx deployment/service specs

[sjberman]

Is your enhancement request related to a problem? Please describe.
There are many Deployment and Service fields that can be customized, and having to expose all of them in the NginxProxy resource is tedious and unnecessary for uncommonly used fields.

What would you like to be added:
Add a way to submit custom patches to unblock users who need to set fields that are not yet exposed in the NginxProxy CRD.

Why this is needed:
Reduce blockages for fields that users need to have set.

Acceptance

• User has a method to patch deployment and service objects provisioned by NGF with Kubernetes patch JSON
• Default patch type is StrategicMerge
• The data plane configuration doc is updated to demonstrate how patches can be applied to provisioned objects.

Dev notes

• Patch should accept a Patch Type and raw JSON
• We can use marshaling and patch merging to copy the user patch on top of the deployment/service objects before provisioning.