Templating (#43)

Add new `templating` crate with custom parser/renderer for dealing with
variables

.github/workflows/ci-js.yml

@@ -0,0 +1,16 @@
+on: [push, pull_request]
+
+name: CI (JS)
+
+jobs:
+  test:
+    name: Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: lts/*
+      - run: npm ci
+      - run: npm run lint
+      - run: npm test