Wireless log file transmit feature

[luftaquila]

Currently, the only way to analyze data saved in the TMA-1's SD card is to eject and put the card into the computer, and upload it to the TMA-3.

Ejecting a card is the most annoying step of the procedure. Anyway, TMA-1 has a wireless internet connection.

So TMA-1 can transfer a saved log file to the TMA-3 over wireless when requested.

Feature idea:

1. TMA-3 requests a log file list
2. TMA-2 server requests TMA-1 to send a log file list
3. ESP32 receives the request and informs STM32 about the request (by an additional wire ESP_REQ)
4. STM32 enters log transmitting mode, aborting all data logging job and disabling all interrupts
5. STM32 reads the SD card and transmits the log file list to ESP32 via I2C
6. ESP32 hand out the log file list to TMA-2, and TMA-2 passes the list to TMA-3
7. A specific log file transfer request made by TMA-3 is sent to ESP32 through the TMA-2
8. ESP32 requests STM32 to transmit the specific log file
9. STM32 transmit the log file to ESP32 via I2C. The log file will be sliced into chunks since ESP32 cannot hold the whole log file in a memory.
10. ESP32 transfers the log file chunk to TMA-2
11. TMA-2 assembles the log file and pass it to the TMA-3