[chirp_devel] Patch for Issue #5595, new BJ-218 Driver

Attached is the first release of the proposed new Baojie BJ-218 driver with full dual-vfo settings. This should probably replace the Luiton Lt725uv, since it declares that radio as an alias of the BJ-218. Related issues: #5595 (this new driver), and #5407, #4645 requests for BJ-218 support.