Add sample proof bundle configurations and verification script

- Introduced sample proof bundle configuration files for testing, including `sample-proof-bundle-config.dsse.json`, `sample-proof-bundle.dsse.json`, and `sample-proof-bundle.json`.
- Implemented a verification script `test_verify_sample.sh` to validate proof bundles against specified schemas and catalogs.
- Updated existing proof bundle configurations with new metadata, including versioning, created timestamps, and justification details.
- Enhanced evidence entries with expiration dates and hashes for better integrity checks.
- Ensured all new configurations adhere to the defined schema for consistency and reliability in testing.

tests/Vex/ProofBundles/cas/graph.json.dsse.json

@@ -0,0 +1,19 @@
+{
+  "payloadType": "application/vnd.stellaops+json",
+  "payload": "ewogICJncmFwaF92ZXJzaW9uIjogInJpY2hncmFwaC12MSIsCiAgInJvb3QiOiAicGtnOmRlbW8vYXBwQDEuMC4wIiwKICAibm9kZXMiOiAzLAogICJlZGdlcyI6IDIsCiAgImhhc2hpbmciOiAiYmxha2UzLTI1NiIsCiAgImdlbmVyYXRlZF9hdCI6ICIyMDI1LTEyLTAzVDIzOjQ1OjAwWiIsCiAgInBhdGhzIjogWwogICAgewogICAgICAiZnJvbSI6ICJwa2c6ZGVtby9hcHBAMS4wLjAjbWFpbiIsCiAgICAgICJ0byI6ICJwa2c6ZGVtby9saWJAMS4wLjAjcmVuZGVyIgogICAgfSwKICAgIHsKICAgICAgImZyb20iOiAicGtnOmRlbW8vbGliQDEuMC4wI3JlbmRlciIsCiAgICAgICJ0byI6ICJwa2c6ZGVtby9saWJAMS4wLjAjaGVscGVyIgogICAgfQogIF0KfQo=",
+  "signatures": [
+    {
+      "keyid": "demo-root",
+      "sig": "USa7UXD1aQyBm6v4gGSBsbQAnMd7IXG1Kw+HwQBXpnU="
+    }
+  ],
+  "subject": [
+    {
+      "name": "graph.json",
+      "hashes": {
+        "sha256": "34d8051bb97bd3c034e6a2221474ce2faaaca59357721fa1b47df88a281d057b",
+        "blake3": "74640754695e6e5cda4156a0ef1fd3a557d802ef118fef8afaed67089cd39cb1"
+      }
+    }
+  ]
+}