tools: Wrap flash binaries into a UF2 file for flashing through USB MSC

@mmoskal This commit adds basic support for UF2 into ESP-IDF.

tools/cmake/project.cmake

@@ -494,6 +494,9 @@ macro(project project_name)
     # Add DFU build and flash targets
     __add_dfu_targets()
 
+    # Add UF2 build targets
+    __add_uf2_targets()
+
     idf_build_executable(${project_elf})
 
     __project_info("${test_components}")