[FL-3174] Dolphin builder in ufbt; minor ufbt/fbt improvements (#2601)

* ufbt: added "dolphin_ext" target (expects "external" subfolder in cwd with dolphin assets); cleaned up unused code
* ufbt: codestyle fixes
* scripts: fixed style according to ruff linter
* scripts: additional cleanup & codestyle fixes
* github: pass target hw code when installing local SDK with ufbt
* ufbt: added error message for missing folder in dolphin builder
* scripts: more linter fixes
* sdk: added flipper_format_stream; ufbt: support for --extra-define
* fbt: reduced amount of global defines
* scripts, fbt: rearranged imports

Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>

scripts/runfap.py

@@ -1,14 +1,12 @@
 #!/usr/bin/env python3
 
+import operator
+from functools import reduce
+
 from flipper.app import App
 from flipper.storage import FlipperStorage, FlipperStorageOperations
 from flipper.utils.cdc import resolve_port
 
-import os
-import posixpath
-from functools import reduce
-import operator
-
 
 class Main(App):
     def init(self):
@@ -38,8 +36,8 @@ class Main(App):
         self.parser.set_defaults(func=self.install)
 
     @staticmethod
-    def flatten(l):
-        return reduce(operator.concat, l, [])
+    def flatten(item_list):
+        return reduce(operator.concat, item_list, [])
 
     def install(self):
         self.args.sources = self.flatten(self.args.sources)