fbt: source collection improvements (#3181)

* fbt: reduced amount of redundant compilation units
* fbt: added GatherSources() method which can reject source paths starting with "!" in sources list; optimized apps' source lists
* docs: updated on path exclusion for `sources`
* apps: examples: fixed example_advanced_plugins source list
* docs: more details on `sources`; apps: narrower sources lists

applications/main/infrared/application.fam

@@ -7,6 +7,7 @@ App(
     icon="A_Infrared_14",
     stack_size=3 * 1024,
     order=40,
+    sources=["*.c", "!infrared_cli.c"],
     resources="resources",
     fap_libs=["assets"],
     fap_icon="icon.png",
@@ -18,5 +19,10 @@ App(
     apptype=FlipperAppType.STARTUP,
     targets=["f7"],
     entry_point="infrared_on_system_start",
+    sources=[
+        "infrared_cli.c",
+        "infrared_brute_force.c",
+        "infrared_signal.c",
+    ],
     order=20,
 )