fbt: fixes (#1352)

* fbt: added --git-tasks; fixed typos
* fbt: fixed --extra-int-apps handling; scripts: moved storage.py & selfupdate.py to App() framework
* fbt: changed pseudo-builders to PhonyTargets with commands; added link to latest build dir as build/latest
* fbt: Restored old ep git handling
* fbt: dropped git tasks & dirlink.py
* fbt: removed extra quoting in fbt.cmd
* docs: added flash_usb to ReadMe.md

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

fbt_options.py

@@ -46,7 +46,7 @@ OPENOCD_OPTS = '-f interface/stlink.cfg -c "transport select hla_swd" -f debug/s
 SVD_FILE = "debug/STM32WB55_CM4.svd"
 
 FIRMWARE_APPS = {
-    "default": (
+    "default": [
         "crypto_start",
         # Svc
         "basic_services",
@@ -62,11 +62,11 @@ FIRMWARE_APPS = {
         "basic_plugins",
         # Debug
         "debug_apps",
-    ),
-    "unit_tests": (
+    ],
+    "unit_tests": [
         "basic_services",
         "unit_tests",
-    ),
+    ],
 }
 
 FIRMWARE_APP_SET = "default"