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>

scripts/flipper/app.py

@@ -1,7 +1,6 @@
 import logging
 import argparse
 import sys
-import os
 
 
 class App:

scripts/flipper/utils/cdc.py

@@ -0,0 +1,17 @@
+import serial.tools.list_ports as list_ports
+
+# Returns a valid port or None, if it cannot be found
+def resolve_port(logger, portname: str = "auto"):
+    if portname != "auto":
+        return portname
+    # Try guessing
+    flippers = list(list_ports.grep("flip"))
+    if len(flippers) == 1:
+        flipper = flippers[0]
+        logger.info(f"Using {flipper.serial_number} on {flipper.device}")
+        return flipper.device
+    elif len(flippers) == 0:
+        logger.error("Failed to find connected Flipper")
+    elif len(flippers) > 1:
+        logger.error("More than one Flipper is attached")
+    logger.error("Failed to guess which port to use. Specify --port")