feat: add per-resource prewarmDevDB override

[WoahitsJoe]

Summary

Adds a per-resource spec.prewarmDevDB override for both AtlasSchema and AtlasMigration.

Today prewarmDevDB is only configurable at the operator level. In multi-tenant/platform setups this is too coarse, because
some managed databases should keep the dev DB warm while others should scale it down after reconciliation.

Changes

• add spec.prewarmDevDB to AtlasSchema
• add spec.prewarmDevDB to AtlasMigration
• resource-level override falls back to the operator-wide prewarmDevDB default
• update controller logic, deepcopy methods, CRDs, and chart CRD template
• add unit coverage for the override behavior
• update docs

Why this approach

I initially considered namespace-level override, but per-resource control seemed like the better API because:

• it avoids namespace-wide coupling
• it matches the granularity of AtlasSchema / AtlasMigration
• it lets app teams opt in only for the resources that benefit from warm dev DBs

Notes

I was not able to run go test / codegen in my local environment for this PR because the Go toolchain was unavailable in that environment, so please let me know if you want me to adjust any generated files.

[giautm]

Your PR changing too much on all files. Please use \n instead of \r\n for newline.

[WoahitsJoe]

@giautm Should be good to go now. Thanks!