[FL-2859,2838] fbt: improvements for FAPs (#1813)

* fbt: assets builder for apps WIP
* fbt: automatically building private fap assets
* docs: details on how to use image assets
* fbt: renamed fap_assets -> fap_icons
* fbt: support for fap_extbuild field
* docs: info on fap_extbuild
* fbt: added --proxy-env parame ter
* fbt: made firmware_cdb & updater_cdb targets always available
* fbt: renamed fap_icons -> fap_icon_assets
* fbt: deprecated firmware_* target names for faps; new alias is "fap_APPID"
* fbt: changed intermediate file locations for external apps
* fbt: support for fap_private_libs; docs: updates
* restored mbedtls as global lib
* scripts: lint.py: skip "lib" subfolder
* fbt: Sanity checks for building advanced faps as part of fw
* docs: info on fap_private_libs; fbt: optimized *.fam indexing
* fbt: cleanup; samples: added sample_icons app
* fbt: moved example app to applications/examples
* linter fix
* docs: readme fixes
* added applications/examples/application.fam stub
* docs: more info on private libs

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

site_scons/fbt/appmanifest.py

@@ -23,6 +23,22 @@ class FlipperAppType(Enum):
 
 @dataclass
 class FlipperApplication:
+    @dataclass
+    class ExternallyBuiltFile:
+        path: str
+        command: str
+
+    @dataclass
+    class Library:
+        name: str
+        fap_include_paths: List[str] = field(default_factory=lambda: ["."])
+        sources: List[str] = field(default_factory=lambda: ["*.c*"])
+        cflags: List[str] = field(default_factory=list)
+        cdefines: List[str] = field(default_factory=list)
+        cincludes: List[str] = field(default_factory=list)
+
+    PRIVATE_FIELD_PREFIX = "_"
+
     appid: str
     apptype: FlipperAppType
     name: Optional[str] = ""
@@ -45,6 +61,9 @@ class FlipperApplication:
     fap_description: str = ""
     fap_author: str = ""
     fap_weburl: str = ""
+    fap_icon_assets: Optional[str] = None
+    fap_extbuild: List[ExternallyBuiltFile] = field(default_factory=list)
+    fap_private_libs: List[Library] = field(default_factory=list)
     # Internally used by fbt
     _appdir: Optional[object] = None
     _apppath: Optional[str] = None
@@ -88,6 +107,12 @@ class AppManager:
                 ),
             )
 
+        def ExtFile(*args, **kw):
+            return FlipperApplication.ExternallyBuiltFile(*args, **kw)
+
+        def Lib(*args, **kw):
+            return FlipperApplication.Library(*args, **kw)
+
         try:
             with open(app_manifest_path, "rt") as manifest_file:
                 exec(manifest_file.read())