Auto merge of #63242 - pietroalbini:move-azure-pipelines, r=Mark-Simulacrum

ci: move .azure-pipelines to src/ci/azure-pipelines

As discussed in the last infra meeting this PR moves the Azure Pipelines configuration to `src/ci/azure-pipelines`, to clean up the root directory.

r? @Mark-Simulacrum

src/ci/docker/x86_64-gnu-tools/repo.sh

@@ -5,7 +5,8 @@
 #
 # The function relies on a GitHub bot user, which should have a Personal access
 # token defined in the environment variable $TOOLSTATE_REPO_ACCESS_TOKEN. If for
-# some reason you need to change the token, please update `.azure-pipelines/*`.
+# some reason you need to change the token, please update the Azure Pipelines
+# variable group.
 #
 #   1. Generate a new Personal access token:
 #