Implement native APRS Telemetry, Definition Messages (PARM/UNIT/EQNS), and RF optimizations

[agafford-ST]

Implement native APRS Telemetry, Definition Messages (PARM/UNIT/EQNS), and RF optimizations

This PR transitions the LightAPRS-2.0 firmware from using comment-field telemetry to fully protocol-compliant, native APRS Telemetry (T# packets). By separating the location data from the environmental data, this update significantly improves RF bandwidth efficiency and enables native, fully scaled charting on aprs.fi and standard APRS desktop clients.

Key Firmware Enhancements (Across all 3 .ino sketches):

• Native Telemetry Integration: Replaced the heavy comment-string telemetry with standard sequence-tracked T# packets containing Battery, Temperature, Pressure, TxCount, and Satellites.
• Automated Telemetry Definitions: Added automated, non-blocking background timers to broadcast PARM, UNIT, and EQNS messages, allowing receiving servers to automatically generate accurate dashboards.
• User-Configurable Variables: Exposed TelemetryDefInitialDelay and TelemetryDefInterval variables in the top configuration block so users can easily manage how often definition messages are broadcast.
• RF Airtime Optimization: Refactored the transmit routine (sendLocationAndTelemetry) to broadcast back-to-back location and telemetry packets within a single RadioON/RadioOFF hardware cycle, significantly reducing overall PTT time and battery drain.

Library Updates Included (ZeroAPRS.h & ZeroAPRS.cpp):

• Added APRS_PrepeareMsg() and APRS_sendMsg() to correctly format standard AX.25 Message data-type headers (:).
• Added APRS_PrepeareTelemetry() and APRS_sendTelemetry() to correctly format standard AX.25 Telemetry data-type headers (T#).

Testing Completed:

• Compiled and successfully tested on physical hardware.
• Verified across all three operating profiles (HAB, Pico-Balloon, and Vehicle).
• Confirmed flawless parsing of T# sequences and PARM/UNIT/EQNS definitions by the APRS-IS network (aprs.fi).
• Verified RF transmission sequence properly keys the DRA818V module and is accurately decoded by terrestrial IGates.