Merge 'Increase warning level & Fix all warnings'

.gitlab-ci.yml

bootloader/crc_patch.py

epicardium/api/caller.c

epicardium/api/dispatcher.c

epicardium/api/interrupt-sender.c

epicardium/ble/ble_main.c

epicardium/epicardium.h

epicardium/l0der/l0der.c

epicardium/modules/bhi.c

epicardium/modules/config.c

epicardium/modules/hardware.c

epicardium/modules/max30001.c

epicardium/modules/personal_state.c

epicardium/modules/serial.c

epicardium/modules/sleep.c

hw-tests/ecgtest/main.c

lib/card10/card10.c

lib/card10/portexpander.c

lib/ff13/meson.build

lib/gfx/framebuffer.c