refactor how the generator for the module_firmware_index.json works (#84)

* remove old loader sketch

* rename and reordered loader sketches

* rename uno wifi r2 using true fqbn

* rename nano rp 2040 connect using true fqbn

* rename mkr1000 using true fqbn

* add loader sketch for mkrvidor

* refactor how the firmwares and loaders generation works

* apply formatting

* fix C901 'generate_boards_json' is too complex

* rename firmware files to include the name of the module used

* make function to retrieve firmware names generic: name now depends on the module

* apply suggestions by @silvanocerza

Author: umbynos