added 'RapidoTZ Hotend Mod V1.0' to Usermods

[Crackzero]

Which mods are added by this PR?

We created a guide to build the RapidoTZ hotend for Voron Stealthburner, a modified Bambu Lab TZ 2.0 hotend with an extended melt zone using a Volcano nozzle and copper nuts, effectively transforming it into a Rapido V2.0-like hotend. Facing layer adhesion problems and flow rate drop-off.

How was it tested?

Running since 2 months in our Stealthburner.

Any background context you want to provide?

In the past, we've encountered several issues with the Pheatus Rapido 1.0 hotend: clogging in the heatbreak, the heatbreak becoming bend in the cooling zone (preventing filament from passing through), faulty heater and temperature sensor, and stripped screws. With the release of the Rapido 2.0 and the Bambu TZ 2.0 hotend, we had the idea to create a low-cost, high-performance hotend accessible to everyone. We're presenting the result here.

Screenshots (if appropriate)

https://youtu.be/uBIikwfB0nQ

⚠️⚠️PLEASE READ AND COMPLETE THE CHECKLIST BELOW⚠️⚠️

• [ x] I have read the rules available here and
  my mod adheres to these rules.
• [ x] This mod was created by myself and I agree to publish it under the repository
  license