Support learning mode w/ proper timer delays

v0.4.9

use dedicated pca counter on efm8bb1 after all

Support learning mode

Original portisch used two hardware timers for microsecond and millisecond delays.
Previously we tried to accomplish delays with one timer but this was failing for bridge users.

So now the "architecture" matches original portisch using two timers.
This also required making optimizations to fit into code space.

With learning mode RF-Bridge-OB38S003 should now be feature complete.

Fix beep duration and state logic

v0.4.6

record original dosniffing logic in comment

Support mcu/radio reset

Support software reset of microcontroller (mainly for testing purposes):
rfraw AA FE 55

RF-Bridge-OB38S003

Special thanks to @zd3sf for testing with ESPHome:
#11

Most major features appear working, excepting learning codes.

rcswitch 0xA5 and 0xA8, and portisch 0xB0 and 0xB1 supported on both sonoff black and white boxes

Use this tool to convert sniffed output (0xB1) to a replay command (0xB0):
https://bbconv.hrbl.pl/

This has only been tested with door sensor using standard protocol timings and 24 bits of data.
Testing of other devices is ongoing here:
#11

v0.3.0

Supporting both Sonoff white and black boxes now.

Passthrough mode

We now produce two firmware files.
The passthrough mode hex file needs to be kept short because flashing has to be copied line by line manually at present.