Add initial README for ESCC board

This commit introduces a new README for the ESCC board detailing the pinout configurations and connections between the Molex connector and IONIQ harness and radar components. The documentation provides a clear, structured guide to assist with proper wiring and setup.

Improving comments for clarity and explicitness

IDE is behaving now. Wd don't need this hack anymore

Add ESCC build option and refine ESCC specific code

Introduce --escc option in SCons to conditionally build ESCC firmware. Update build_project to support CPPDEFINES and modify main.c to handle ESCC-specific safety modes and behaviors more cleanly.

Remove unnecessary send_escc_msg calls in Hyundai safety code

The updates in the code remove redundant send_escc_msg calls in the Hyundai safety code. We don't really need to send the FCA or AEB data through the ESCC packet because we don't block it at all. So we don't really need to "package" it anymore on the ESCC message

Add send_escc_msg call in case blocks

The send_escc_msg function is now called within the individual case blocks for SCC11, SCC12, and FCA11, enhancing code readability. Before, it was called on any message that the radar sends, but this strategy was inefficient as it was piggybacking on their frequencies.

Refactor `escc_tx_hook` function in Hyundai safety code

The commented-out `escc_tx_hook` function in Hyundai ESCC safety code has been refactored and is now in use again, replacing the formerly used `alloutput_tx_hook`. Debugging functionality has been preserved and conditions for when the function is unused have also been handled. The resulting code is now cleaner and more efficient.

Add ESCC firmware and build files, and safety mode for Hyundai ESCC

This commit introduces ESCC firmware and the corresponding build files. We have also defined a new safety mode for Hyundai ESCC. The necessary scripts for flashing and recovery have been added, alongside the gitignore file for the ESCC board. Additionally, we have implemented new message processing and forwarding logic to handle ESCC specific messages in main and safety files.