[RTL] Convert APB interfaces to AXI and add DMA

[calebofearth]

Changelist

• Convert soc_ifc APB slave interface to AXI subordinate.
• Add new AXI DMA to Caliptra soc_ifc with AXI manager to enable Caliptra Active mode.
• Update caliptra_top_tb to support AXI based testing, use AXI tasks instead of FSM for r/w, add smoke tests for AXI bringup and DMA operations.
• Ensure Verilator still works on the AXI TB

Still TODO

• Migrate UVM environment from APB to AXI
• Update soc_ifc directed register tests for AXI
• Comprehensive testplan for AXI DMA functionality
• Verify the Flush functionality for AXI DMA

Task tracking

Resolves #563
Resolves #564