fedora-intune: use Himmelblau instead of the Microsoft Intune app

Go with Entra ID sign-in through Himmelblau for fedora-intune and drop
the Microsoft Intune app (intune-portal, identity broker) variant. With
a single image, the workstation, Edge and Defender manifests move back
from images/shared into images/fedora-intune, and CI builds just that
image again. The Microsoft repo is now limited to mdatp and Edge.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

build.sh

@@ -201,10 +201,7 @@ case "${BUILD_MODE}" in
     if [[ -d "${IMAGE_DIR}/files" ]]; then
       cp -a "${IMAGE_DIR}/files/." "${BUILD_DIR}/upstream/"
     fi
-    # Shared overlay (manifests/files/repos used by multiple images).
-    if compgen -G "${REPO_ROOT}/images/shared/*.yaml" >/dev/null; then
-      cp "${REPO_ROOT}"/images/shared/*.yaml "${BUILD_DIR}/upstream/"
-    fi
+    # Shared overlay (files/repos used by multiple images).
     if [[ -d "${REPO_ROOT}/images/shared/files" ]]; then
       cp -a "${REPO_ROOT}/images/shared/files/." "${BUILD_DIR}/upstream/"
     fi