chore(epicardium): Move all core1 code into a separate subdir

epicardium/ble/epic_ble_api.c

epicardium/drivers/bhi.c

epicardium/drivers/max30001.c

epicardium/drivers/max86150.c

epicardium/drivers/pmic.c

epicardium/drivers/rtc.c

epicardium/drivers/serial.c

epicardium/fs/filesystem_fat.c

epicardium/main.c

epicardium/meson.build

epicardium/modules/hardware.c

epicardium/modules/meson.build

epicardium/modules/modules.h

epicardium/support.c

epicardium/user_core/dispatcher.c

epicardium/user_core/interrupts.c

epicardium/user_core/interrupts.h

epicardium/user_core/lifecycle.c

epicardium/user_core/meson.build

epicardium/user_core/user_core.h