Meshtastic Firmware Release Notes

This is where I will be adding my own understanding on what each release note does in a simple easy way to explain it.

Meshtastic Firmware 2.5.6.ad8747d Alpha Pre-release

RAK4631 Ethernet Gateway with working JSON output to MQTT by @beegee-tokyo in #4661
Alternate variant support for Ethernet Gateway module RAK13800 for MQTT+JSON uplink for RAK4631 (not on webflasher).
Preliminary Othernet Dreamcatcher Support by @caveman99 in #4933
Support for Othernet Dreamcatcher board.
Toggle Bluetooth with Fn+b shortcut by @HarukiToreda in #4977
New key combination to toggle Bluetooth on/off on Cardkb devices.
Add health telemetry module by @fifieldt and @thebentern in #4927
New Health Telemetry module using the MLX90614 IR temperature and MAX30102 temperature/oxygen saturation/heart rate sensors.
First version of a DeepSleep state for the RP2040 by @TheMalkavien in #4976
Initial support for DeepSleep for RP2040 (Raspberry Pi) boards.
Add frequencies for the Philippines by @fifieldt in #4951

Which Module wants a UI Frame? by @fifieldt in #4967
Improvement to debug reporting.
UserPrefs - Preconfigure up to 3 channels, GPS Mode by @medentem in #4930
Improvement to firmware building.
Start of generating JSON manifest of macros in userPrefs.h by @thebentern in #4946
Improvement to firmware building.
Coalesce duplicated method GetTimeSinceMeshPacket by @fifieldt in #4968
Cleanup for debug reporting.
Upgrade nanopb by @thebentern in #4973
Improvement for Protobuf (Protocol Buffers, a data format used to serialize structured data).

Remove unused Jlink monitoring files by @fifieldt in #4953
Maintenance.
Retire PPR Boards by @fifieldt in #4956
PPR and PPR1 board variants removed.
Retire LoRa-relay boards by @fifieldt in #4957
LoRa-relay board variants removed.
Remove support for pca10056-rc-clock by @fifieldt in #4955
pca10056-rc-clock board variants removed.
Remove unused headers by @fifieldt in #4954
Cleanup.
Fix storage of admin key when installing default config by @Mictronics in #4995
Fix storage of admin key after reset issue.