test/run/stages: convert test_selinux to a v2 manifest

Let's not depend on f34-base.json anymore, but instead of a separate,
standardized manifest for it. The test was modified so it supports
v2 manifests. Also, the new manifest installs just a very minimal system.
There's no need to install the whole @core.

test/data/stages/selinux/manifest.mpp.yaml

@@ -0,0 +1,30 @@
+version: '2'
+pipelines:
+  - mpp-import-pipelines:
+      path: ../manifests/fedora-vars.ipp.yaml
+  - mpp-import-pipeline:
+      path: ../manifests/fedora-build-v2.ipp.yaml
+      id: build
+    runner:
+      mpp-format-string: org.osbuild.fedora{release}
+  - name: tree
+    build: name:build
+    stages:
+      - type: org.osbuild.rpm
+        inputs:
+          packages:
+            type: org.osbuild.files
+            origin: org.osbuild.source
+            mpp-depsolve:
+              architecture: $arch
+              module-platform-id: $module_platform_id
+              repos:
+                mpp-eval: repos
+              packages:
+                - systemd
+                - selinux-policy-targeted
+        options:
+          gpgkeys:
+            mpp-eval: gpgkeys
+          exclude:
+            docs: true

test/run/test_stages.py

@@ -277,19 +277,15 @@ class TestStages(test.TestBase):
         datadir = self.locate_test_data()
         testdir = os.path.join(datadir, "stages", "selinux")
 
-        def load_manifest(manifest_name):
-            with open(os.path.join(datadir, f"manifests/{manifest_name}"), encoding="utf8") as f:
-                manifest = json.load(f)
-                return manifest
-
         with self.osbuild as osb, tempfile.TemporaryDirectory(dir="/var/tmp") as outdir:
 
             for t in glob.glob(f"{testdir}/test_*.json"):
-                manifest = load_manifest("f34-base.json")
+                with open(os.path.join(testdir, "manifest.json"), encoding="utf8") as f:
+                    manifest = json.load(f)
                 with open(t, encoding="utf8") as f:
                     check = json.load(f)
-                manifest["pipeline"]["stages"].append({
-                    "name": "org.osbuild.selinux",
+                manifest["pipelines"][1]["stages"].append({
+                    "type": "org.osbuild.selinux",
                     "options": check["options"]
                 })