USB gadget: Drop g_multi in favor of librem5-base

Draft, because I can't get the .deb to build and test it properly.

Draft, because the MAC should be done as a systemd enviroment variable, to prevent resetting at every upgrade.

Draft, because it's based on !220 (merged)

debian/changelog

+librem5-devkit-tools (0.0.19pureos1) byzantium; urgency=medium
+
+  * d/control: Depend on librem5-flash-image
+  * Don't install flashing scripts.
+    These were split out to a separate repo. Keep the scripts around but
+    don't install them in the package until all the docs got updated.
+    See https://source.puri.sm/Librem5/librem5-devkit-tools/-/issues/40
+
+ -- Guido Günther <agx@sigxcpu.org>  Thu, 12 Aug 2021 10:15:19 +0200
+
+librem5-devkit-tools (0.0.18pureos1) byzantium; urgency=medium
+
+  [ Dorota Czaplejewicz ]
+  * ci: Build arm64 package too
+
+  [ Evangelos Ribeiro Tzaras ]
+  * ci: drop --dist parameter to use the defaults
+
+  [ Angus Ainslie ]
+  * librem5-devkit.conf: set the operating mode to bluetooth EDR
+
+ -- Angus <angus@midas.akkea.ca>  Mon, 09 Aug 2021 05:57:39 -0700
+
 librem5-devkit-tools (0.0.17pureos1) byzantium; urgency=medium
 
   * tests: Check for CSI controller