- re-enable once the estimator selector respects configured mag
priority (at least initially) or is otherwise able to automatically
prefer an external mag over internal
- for SITL disabled because the full matrix of esitmator instances
(IMUs X mags) was too many topics for logger currently
- cmake NuttX build wrapper compile in place instead of copying source tree to build directory
- slightly faster skipping necessary copying (depending on system)
- allows debugging in place
- easier to work directly in NuttX following official documentation
- simplifies overall build which should make it easier to resolve any remaining NuttX dependency issues in the build system
- the downside is switching back and forth between different builds always require rebuilding NuttX, but I think this is worth the improved developer experience
- also no longer builds px4io and bootloader in every single build, for most users these rarely change and we're wasting a lot of build time
