NuttX build in place

- 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

.vscode/settings.json

@@ -14,7 +14,6 @@
         "C_Cpp.workspaceParsingPriority": "low",
         "cmake.buildBeforeRun": true,
         "cmake.buildDirectory": "${workspaceFolder}/build/${variant:CONFIG}",
-        "cmake.buildTask": true,
         "cmake.configureOnOpen": true,
         "cmake.ctest.parallelJobs": 1,
         "cmake.skipConfigureIfCachePresent": true,