adds initial rescript structure

rescript/jest.config.js

@@ -0,0 +1,14 @@
+module.exports = {
+  moduleFileExtensions: [
+    "js",
+    "mjs",
+  ],
+  testMatch: [
+    "**/src/**/*_test.mjs",
+    "**/src/**/*_test.bs.js",
+  ],
+  transform: {
+    "^.+\\.jsx?$": "esbuild-jest"
+  },
+  "transformIgnorePatterns": ["<rootDir>/node_modules/(?!(rescript|@glennsl/rescript-jest)/)"]
+}