* Start working on fixing doxygen warnings

* Upgrade doxyfile to Doxygen 1.9.1

* Clean up some unmatched groups and add some exclusions

* Fix docs for rtos::ThisThread not showing up

* Fix up KV store docs

* Fix incorrect @files, some more incorrect groups

* Fix lots of broken links

* Start fixing mbedtls groups

* Fix more mbedtls docs

* Fix remaining mbedtls files with missing or incorrect grouping

* Fix a huge amount of PSA docs errors

* Fix a few more mbedtls docs errors

* Fix __cplusplus not defined for docs, clean up call in callback typedef, fix some docs errors

* Fix some broken doc links in HAL headers

* Fix more PSA doc errors

* Fix some doxygen errors in networking code

* Fix lots of network related doc errors

* Try and fix some CI failures

* Use Doxygen Action instead of doxygen in Mbed container to get the right version

* Try removing docs check

* Add first part of doxygen action

* Add next part of doxygen action

* Fix yaml syntax error

* Add in license check fix

* Try using verbose scancode

* Fix some more docs issues, workaround scancode-toolkit#3179

* Clean up the LoRaRadio get_state() function on each implementation.  Also fix some other compile and doc errors.

* Fix all remaining doxygen errors

* Fix escaping, for realsies this time

* Remove Doxygen unsupported config options, fix some more get_status() declarations

* Fix some UNITTESTS build errors

* Fix one more compile error

* Another unittest error

* Clean up group definitions in doxygen

* remove THIRD_PARTY_DOCS

* some stragglers

* fix astyle formatting

Some LoRaWAN modem like SX1272 can receive downlink packets with RSSI level less than -127. So "int8_t" is not enough for store all possible RSSI values. For example, SX1272 has sensitivity at -137 dBm.
Problem was manifested in the file "SX1272_LoRaRadio.cpp" at SX1272_LoRaRadio::handle_dio0_irq() method.
When value of _rf_settings.lora_packet_handler.rssi_value calculated incorrect RSSI will be stored. Example case:

Value readen from register REG_LR_PKTSNRVALUE _rf_settings.lora_packet_handler.snr_value equals -47.
Value readen from register REG_LR_PKTRSSIVALUE equals 17.
RSSI_OFFSET equals "-139", snr equals "-11".

For case MODEM_LORA value calculated by formula:
_rf_settings.lora_packet_handler.rssi_value = RSSI_OFFSET + rssi + (rssi >> 4) + snr;
and result value will be "124" because of int8_t overflow so it's not correct value (too high).

Correct value must be:
-139 + 17 + (1) + (-11) = -132.

Another motivation: at all other places int16_t type used to store RSSI value.