[FL-2627] Flipper applications: SDK, build and debug system (#1387)

* Added support for running applications from SD card (FAPs - Flipper Application Packages)
* Added plugin_dist target for fbt to build FAPs
* All apps of type FlipperAppType.EXTERNAL and FlipperAppType.PLUGIN are built as FAPs by default
* Updated VSCode configuration for new fbt features - re-deploy stock configuration to use them
* Added debugging support for FAPs with fbt debug & VSCode
* Added public firmware API with automated versioning

Co-authored-by: hedger <hedger@users.noreply.github.com>
Co-authored-by: SG <who.just.the.doctor@gmail.com>
Co-authored-by: あく <alleteam@gmail.com>

.gitmodules

@@ -28,3 +28,6 @@
 [submodule "lib/mbedtls"]
 	path = lib/mbedtls
 	url = https://github.com/Mbed-TLS/mbedtls.git
+[submodule "lib/cxxheaderparser"]
+	path = lib/cxxheaderparser
+	url = https://github.com/robotpy/cxxheaderparser.git