[XAP] add binding for dynamic macros

XAP Task Info

Original Issue Original spec document Current XAP Definitions Current XAP Generated Docs Placeholder PR

Description

Any work in this area needs to be discussed with QMK Collaborators first.

Add support for routes to expose a dynamic macro subsystem, matching VIA/VIAL capabilities.

• Potentially its own route and not coupled to #15629.
• Potentially unify dynamic_keymap_macros and dynamic_macros?
• Decouple dynamic_keymap_macros from dynamic_keymap?
• Ensure feature parity with send_string (inc SS_DELAY_CODE)?