Scripting: SoarNav: Add new feature-rich applet for autonomous soaring

SoarNav is an advanced Lua script for intelligent, autonomous soaring
that enhances ArduPilot's capabilities. It uses a suite of strategic
features to maximize flight time within a defined area.
The script employs a hybrid exploration strategy, dynamically balancing
the search for new grid cells with guided re-visiting of the least
explored areas based on recent thermal success. This is coupled with an
intelligent thermal memory that saves thermal core locations. A
sophisticated clustering algorithm then identifies promising hot zones
using a weighted score based on nearby thermals' strength, age, and
proximity.
Real-time thermal analysis is performed using adaptive sampling for a
responsive strength calculation. The script is architected for robust
performance with a modular state machine and parameter caching. Safety
is enhanced with dynamic anti-stuck logic, tactical rerouting, and
thermal street detection capabilities.

Author: robustini