Integrate gitlab-ci/lpag/manifest_fix and 3 more

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Commit: https://git.seco.com/edgehog/infrastructure/gitlab-ci/-/commit/9c6e4e8a1f4becff3d3b5f638975fccfa6c0fff6

[BUILD][BRANCH] Fix bug on BUILD_BRANCH variable

* The build is always triggered via a parent pipeline in this version
of the CI/CD so it was necessary to fix the condition.

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Commit: https://git.seco.com/edgehog/infrastructure/gitlab-ci/-/commit/f8247528bd78a7ec9e633918ad9941873fe6e07b

[THINGS][TEST] Insert test job for Things distro

* This is a first implementation of automatic testing of Things distro
using SECO LAVA lab.
* The test is directed to 4 device types, one for each main architecture
(imx6, imx8, Rockchip, Intel).

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Commit: https://git.seco.com/edgehog/infrastructure/gitlab-ci/-/commit/6fb99d7ee3162ae26f9f7e3648da5f85a20872d1

[DOC] Add info about meta-layer MANIFEST_FILE var

The variable needs to be added as a project variable in order to specify
the manifest file on which the meta-layer needs to be integrated.

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Commit: https://git.seco.com/edgehog/infrastructure/gitlab-ci/-/commit/4653fee34dbaea035e4bec4221339d63c1910702

[FIX] Fix syntax errors in MACHINE parameter

The MACHINE parameter is fundamental in order to match the path of the
built artifacts gin GitLab CI

.gitlab-ci @ 9c6e4e8a

-Subproject commit 943eac764805a486e3ca2538a263ab531fd4c45b
+Subproject commit 9c6e4e8a1f4becff3d3b5f638975fccfa6c0fff6

.gitlab-ci.yml

@@ -4,8 +4,8 @@
 # ---------------------------------------------------------------------------------------
 include:
   - project: '${CI_PROJECT_ROOT_NAMESPACE}/infrastructure/gitlab-ci'
-    ref: 943eac764805a486e3ca2538a263ab531fd4c45b
+    ref: 9c6e4e8a1f4becff3d3b5f638975fccfa6c0fff6
     file: 'manifest-integration.yml'
 
 variables:
-  GITLAB_CI_REVISION: 943eac764805a486e3ca2538a263ab531fd4c45b
+  GITLAB_CI_REVISION: 9c6e4e8a1f4becff3d3b5f638975fccfa6c0fff6