Basically, you should be able to use firewall includes for that. If you want a dedicated ui for it you can use QoSmate and set up custom rules there... explanations are available in the README.
You can also find examples for rate limiting here.
Note: Per-device rate limiting and traffic shaping are fundamentally different. Rate limiting simply drops packets exceeding a threshold... it's stateless and can't really manage latency or bufferbloat.
Proper traffic shaping at your WAN bottleneck (e.g., cake with built-in aqm or hfsc/htb with fq_codel leaves) uses intelligent queuing and AQM algorithms to control bufferbloat while maintaining fairness between flows.
Per-device limits are useful for administrative control (guest networks, quota enforcement) but won't solve bufferbloat. For proper network performance, shape at your wan bottleneck first, then add device limits only where policy requires.