refactor: move transforms/ into infrahub/ and update all paths (#20)

Move transforms/{queries,templates,tests} under infrahub/transforms/ so all
Infrahub-managed content lives under the dedicated infrahub/ directory,
consistent with schemas/, objects/, and menus/.

Updated paths:
- .infrahub.yml: file_path and template_path entries now prefixed with
  infrahub/transforms/
- infrahub/transforms/tests/*/test.yml: directory references updated from
  transforms/tests/* to infrahub/transforms/tests/*

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

infrahub/transforms/tests/vxlan_yang/output.json

@@ -0,0 +1,12 @@
+{
+  "vtep": {
+    "learn_restrict": "any",
+    "source_address": "10.0.255.11/32",
+    "source_interface": "Loopback1",
+    "udp_port": 4789,
+    "vlan_vni_mappings": [
+      {"vlan_id": 40, "vlan_name": "test-l2-vxlan", "vni": 110040, "vni_type": "l2vni"}
+    ],
+    "vrf_vni_mappings": []
+  }
+}