feat: built-in library (#557)

Closes partially #433

### Summary of Changes

* Add the built-in library from the old Xtext version
* Load in into the VS Code workspace

---------

Co-authored-by: megalinter-bot <129584137+megalinter-bot@users.noreply.github.com>

Author: lars-reimann

.eslintrc.cjs

@@ -12,5 +12,6 @@ module.exports = {
     extends: '@lars-reimann',
     rules: {
         'import/extensions': 'off',
+        'vitest/prefer-lowercase-title': 'off',
     },
 };

esbuild.mjs

@@ -1,5 +1,6 @@
 //@ts-check
 import * as esbuild from 'esbuild';
+import { copy } from 'esbuild-plugin-copy';
 
 const watch = process.argv.includes('--watch');
 const minify = process.argv.includes('--minify');
@@ -15,16 +16,26 @@ const padZeroes = function (i) {
     return i.toString().padStart(2, '0');
 }
 
-const plugins = [{
-    name: 'watch-plugin',
-    setup(build) {
-        build.onEnd(result => {
-            if (result.errors.length === 0) {
-                console.log(getTime() + success);
-            }
-        });
+const plugins = [
+    {
+        name: 'watch-plugin',
+        setup(build) {
+            build.onEnd(result => {
+                if (result.errors.length === 0) {
+                    console.log(getTime() + success);
+                }
+            });
+        },
     },
-}];
+    copy({
+        // resolveFrom: 'cwd',
+        assets: {
+            from: ['./src/resources/**/*'],
+            to: ['./resources'],
+        },
+        watch,
+    }),
+];
 
 const ctx = await esbuild.context({
     // Entry points for the vscode extension and the language server
@@ -38,7 +49,7 @@ const ctx = await esbuild.context({
     outExtension: {
         '.js': '.cjs'
     },
-    loader: { '.ts': 'ts' },
+    loader: {'.ts': 'ts'},
     external: ['vscode'],
     platform: 'node',
     sourcemap: !minify,