fbt: compile_db fixes (#1981)

* fbt: forked compilation_db tool
* fbt: fixes for static analysis
* pvs-studio: ignoring more generic warnings
* fbt: util: added extract_abs_dir
* vscode: added fap-set-debug-elf-root for debug configurations

scripts/fbt_tools/fbt_extapps.py

@@ -57,11 +57,12 @@ def BuildAppElf(env, app):
             )
 
     if app.fap_icon_assets:
-        app_env.CompileIcons(
+        fap_icons = app_env.CompileIcons(
             app_env.Dir(app_work_dir),
             app._appdir.Dir(app.fap_icon_assets),
             icon_bundle_name=f"{app.appid}_icons",
         )
+        app_env.Alias("_fap_icons", fap_icons)
 
     private_libs = []