lava: Inline the code that adds the development component

Rather than linking to an external `add-repo` test definition whose only
purpose is to add the `development` APT component to the preconfigured
sources, inline the definition to simplify things.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

lava/common-boot-tpl.yaml

@@ -133,12 +133,20 @@ actions:
           from: git
           path: test-cases/sanity-check.yaml
           name: sanity-check
-        - repository: https://gitlab.apertis.org/pkg/apertis-tests
-          branch: 'apertis/v2023dev0'
-          history: False
-          from: git
-          path: misc/add-repo.yaml
+        - repository:
+            metadata:
+              name: add-repo
+              format: "Lava-Test-Shell Test Definition 1.0"
+              description: "Add the development repository to the APT sources"
+            install:
+              steps:
+              - sed -i '/\bdevelopment\b/! s/^deb \(.*\)/deb \1 development/' /etc/apt/sources.list
+            run:
+              steps:
+              - lava-test-case add-repo --shell grep development /etc/apt/sources.list
+          from: inline
           name: add-repo
+          path: inline/add-repo.yaml
         - repository: https://gitlab.apertis.org/tests/apertis-test-cases.git
           branch: 'apertis/v2023dev0'
           history: False