UI request: move bootloader update button to setup page

#### Issue details
Ref https://github.com/ArduPilot/ardupilot_wiki/issues/1920
It would be great to have the bootloader update button on the firmware or setup page, rather than CTRL-F menu, so it is more obvious for users.

#### Platform
[ x ] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Hardware type
_What autopilot hardware was used?
All stm32

Start by locating the CTRL-F menu and the firmware or setup page in Mission Planner. Move the bootloader update button so it is visible from the setup or firmware page for all supported STM32 hardware, then verify the button remains available and usable.

Written by the indexing model from the issue text.