Add `BadgerDBDelete` method for `ResourceDefinitionModel`

[jim-junior]

Description

Extend the ResourceDefinitionModel struct by adding a new standalone method called BadgerDBDelete. To avoid breaking changes across external system logic, do not refactor or replace the legacy etcd-based Delete implementation. This new capability will introduce standalone support to remove an existing resource definition payload directly from BadgerDB.

Requirements

• File Location: internal/models/resource_definitions.go
• Method Signature Strategy: Introduce a new method named BadgerDBDelete(name string) error on the ResourceDefinitionModel struct.
• Transactionality: Execute the entire removal check and delete block inside a BadgerDB Update (write) transaction to ensure proper synchronization.
• Key Generation: Generate the targeted key using the existing key(name) helper (i.e., /resource_definitions/{name}).
• Existence Verification & Error Handling: * Prior to running the deletion call, explicitly verify whether the key exists inside BadgerDB by trying to retrieve it or using transaction methods.
  • If the key is not found, return a descriptive custom "not found" validation error matching the error context returned by the etcd-based predecessor.
• Testing: Write a dedicated validation test suite inside internal/models/resource_definitions_test.go to prove standalone item removal mechanics.

Success Criteria

• The BadgerDBDelete method is successfully added to the data layer model alongside legacy paths without modifying existing API signatures.
• The operation checks key existence and performs deletion atomically inside a write-safe Update block.
• Attempting to delete a definition name that doesn't exist returns the expected descriptive "not found" error.
• Test Case implementation: A comprehensive unit test is provided that:
  • Seeds an isolated, in-memory BadgerDB instance with a temporary resource definition key and data payload.
  • Successfully calls BadgerDBDelete to strip the key from the dataset.
  • Confirms through a subsequent lookup that the removed key is no longer discoverable in the database.
  • Verifies that invoking the deletion method on an invalid configuration name securely reports the expected error constraint.