Add minunit test framework (#168)

* add minunit tests

* fix logging

* ignore unexisting time service on embedded targets

* fix warning, issue with printf

* add exitcode

* migrate to printf

* indicate test by leds

* add testing description

* redesigned minunit tests to allow testing in separate files

* add test step for local target

* add failure test

* add restore test_check

* testing description

Co-authored-by: rusdacent <rusdacentx0x08@gmail.com>
Co-authored-by: DrZlo13 <who.just.the.doctor@gmail.com>

firmware/targets/local/Src/main.c

@@ -4,10 +4,8 @@ Flipper devices inc.
 Local fw build entry point.
 */
 
-void app();
+int app();
 
 int main() {
-    app();
-
-    return 0;
+    return app();
 }