Utilise FLASH memory as storage for param and dataman

[chengguizi]

Dev C board has no SD Card, we need a generic way to store persistent data, particularly the paramter data.

We plan to use the sector 1 and 2 of the Flash as the paramter space. This is because the later part of the flash is divided by 128K, which is too large and wasteful.

https://www.st.com/resource/en/reference_manual/dm00031020-stm32f405-415-stm32f407-417-stm32f427-437-and-stm32f429-439-advanced-arm-based-32-bit-mcus-stmicroelectronics.pdf

I propose to change the bootloader address from 0x08004000 to 0x0800C000 in this case.

[chengguizi]

Successful FLASH based param, done on Dev A. Bootloader is to be modified to allocate 32K space right after the bootloader. Refer to commit nusrobomaster/PX4-Bootloader@0e44876

For PX4 Firmware, the main changes are (commit 90821e3):

• script.ld to make the proper shift in nuttx address space
• modify init.c to initialise param module's flash-based mode
• change rcS accordingly, primarily the handling of VEHICLE_TYPE (param's SYS_AUTOSTART id)

Note: current EKF2 initialisation logics require magnetometer and barometer, which makes it not usable at this stage. Enabling attitude_estimator_q and local_position_estimator instead to demostrate basic attitude estimator algorithm.