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)

.gitlab-ci.yml

+include:
+ - 'https://source.puri.sm/Librem5/librem5-ci/raw/master/librem5-pipeline-definitions.yml'
+ - 'https://source.puri.sm/Librem5/librem5-ci/raw/master/librem5-pipeline-byzantium-jobs.yml'
+
+stages:
+ - test
+ - package
+ - test-package
+
 variables:
   FLASHDEPS: python3
              python3-coloredlogs
@@ -11,22 +20,6 @@ variables:
   tags:
     - librem5
 
-build:deb:
-  <<: *tags
-  stage: build
-  image: $IMAGE
-  before_script:
-    - export DEBIAN_FRONTEND=noninteractive
-    - apt-get -y update
-    - apt-get -y install org-mode build-essential
-    - apt-get -y build-dep .
-  script:
-    - dpkg-buildpackage -uc -us
-    - cp ../*.deb .
-  artifacts:
-    paths:
-      - '*.deb'
-
 test:download:deb:
   <<: *tags
   stage: test