Allow pre-builtin actions with custom action

[ashutosh16]

Summary

ArgoCD provides a single set of actions, either from resource_customization or from overrides in the ConfigMap. If an ArgoCD operator wants to add any ad-hoc action, it will override the prebuilt actions. This behavior is valid since the override functionality is designed to replace existing actions. However, there are scenarios where a user might want to use both prebuilt actions and custom actions in the ConfigMap.

What change you think needs making.
Add flag in the resource action which when set true on the resources, will add all the actions

Motivation

In ArgoCD, we want to add custom actions to the Rollout object to perform specific tasks. However, we also want to retain the prebuilt actions. Therefore, we need a way to include both the prebuilt actions and the custom actions specified in the overrides.

Please give examples of your use case, e.g. when would you use this.
Rollout actions