build: define the TypeScript configuration files

This commit introduces to the root of the workspace, the `tsconfig.json`
and the `tsconfig.test.json` files, extending the pre-configured
compiler from the `@louffee/tsconfig.json` internal package.

Author: mrlemoos

tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "extends": ["./tsconfig.test.json"],
+  "compilerOptions": {
+    "typeRoots": ["./node_modules/@types", "./_env/@types"]
+  }
+}

tsconfig.test.json

@@ -0,0 +1,3 @@
+{
+  "extends": "@louffee/tsconfig/tsconfig.test.json"
+}