change default deployment name to resource_namespace

[carlydf]

What was changed and Why

We discussed using a . in the past, but the server won't be able to support that before the release of the controller. A / feels off if the ordering is resource/namespace because a resource is a sub-component of a namespace, and / implies file-system type hierarchy.

I had a convo with ChatGPT comparing some options just for fun, and I agree with it that an underscore separator with resource name followed by namespace name feels like the best option.

Checklist

1. Closes

2. How was this tested:
   Integration and unit tests

3. Any docs updates needed?

[Shivs11]

can't seem to load the convo with our new best friend, so don't wanna preemptively approve this rn

[carlydf]

I changed my mind, I think resource/namespace is fine actually