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/interface_yang/test.yml

@@ -0,0 +1,15 @@
+---
+version: "1.0"
+infrahub_tests:
+  - resource: Jinja2Transform
+    resource_name: interface_yang_transform
+    tests:
+      - name: smoke_check
+        spec:
+          kind: jinja2-transform-smoke
+      - name: render_leaf1
+        spec:
+          kind: jinja2-transform-unit-render
+          directory: infrahub/transforms/tests/interface_yang
+          input: input.json
+          output: output.json