android: add Shanwan Twin USB Joystick profile

[danielcamposramos]

Summary

Add an Android autoconfiguration profile for a 2.4 GHz multi-controller USB
receiver that reports:

Device: Shanwan Twin Usb Joystick
VID:    0x20bc / 8380
PID:    0x5500 / 21760

The existing SHANWAN PC_PS3_Android Gamepad.cfg shares the VID/PID but has a
different exact device name, so the profiles do not conflict.

The receiver exposes the physical right-stick horizontal direction as Android
RZ / RetroArch axis 3 and its vertical direction as Android Z / axis 2. The
profile includes PS-style descriptors for all buttons and axes.

Hardware validation

• RetroArch 1.22.2_GIT, Android input driver, Android 10.
• Green two-controller bundle sold under AliExpress item 1005007269278592.
• Both controllers sharing the receiver were tested concurrently.
• Complete mapping was confirmed on controllers 1 and 2: D-pad, face buttons,
  shoulders, triggers, Select, Start, L3/R3, menu button, and both sticks.
• Native analog gameplay was confirmed with Jackie Chan Stuntmaster under
  PCSX-ReARMed. Tekken 3 was also tested separately with its required
  game-specific analog-to-D-pad remap; that remap is intentionally not part of
  this generic hardware profile.
• Repository test result: No duplicate profiles were found.

The seller offers bundles with up to four controllers, but only the two-pad
bundle was physically validated.