Replace Molecule PXE component placeholder assertions with real tests

User Story:

As a developer, I want real test assertions for PXE component so that PXE operator functionality is validated

Problem Statement:

PXE component tests don't validate DHCP configuration, TFTP boot services, or preseed template generation.

Acceptance Criteria:

• PXE CRD creation validated with correct configuration
• DHCP server configuration verified
• TFTP boot file serving tested
• Preseed/kickstart template generation validated
• Network boot sequence simulated.
• MAC address to IP mapping verified
• Idempotency verified (no changes on second run)

Implementation Details:

Files to Modify:

• molecule/default/tasks/pxe_test.yml - Replace placeholder assertions with real tests
• molecule/default/vars/pxe_test_vars.yml - Test data for PXE boot scenarios

Dependencies:

• dhcplib for DHCP testing
• tftpy for TFTP validation.
• kubernetes Python client

Additional Notes:

Verify DHCP lease allocation, validate boot file paths, check preseed template rendering with proper network configurations, and test iPXE chain loading if configured

---