feat: Test running overhaul, switch to Prettier & reformat everything (#1407)

* chore: Switch to Node 20 + Vitest

* chore: migrate to vitest mock functions

* chore: code style (switch to prettier)

* test: re-enable long-running test

Seems the switch to Node 20 and Vitest has vastly improved the code's and / or the test's runtime!

see #1193

* chore: code style

* chore: fix failing tests

* Updated Documentation in README.md

* Update contribution guidelines to state usage of Prettier

* fix: set prettier printWidth back to 80

* chore: apply updated code style automatically

* fix: set prettier line endings to lf again

* chore: apply updated code style automatically

---------

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Lars Müller <34514239+appgurueu@users.noreply.github.com>

package.json

@@ -4,34 +4,20 @@
   "type": "module",
   "description": "A repository for All algorithms implemented in Javascript (for educational purposes only)",
   "scripts": {
-    "test": "jest",
-    "test-changed": "jest --onlyChanged",
-    "style": "standard",
+    "test": "vitest run",
+    "test-watch": "vitest",
+    "style": "npx prettier . --write",
     "prepare": "husky install"
   },
   "author": "TheAlgorithms",
   "license": "GPL-3.0",
-  "dependencies": {
-    "@babel/core": "^7.19.3",
-    "@babel/plugin-transform-runtime": "^7.19.1",
-    "@babel/preset-env": "^7.19.4"
-  },
   "devDependencies": {
-    "@babel/eslint-parser": "^7.19.1",
-    "@types/jest": "^29.1.2",
-    "babel-jest": "^29.2.0",
-    "globby": "^13.1.2",
-    "husky": "^8.0.1",
-    "jest": "^29.2.0",
-    "standard": "^17.0.0"
+    "globby": "^13.2.2",
+    "husky": "^8.0.3",
+    "prettier": "^3.0.3",
+    "vitest": "^0.34.6"
   },
   "engines": {
-    "node": ">=16.6.0"
-  },
-  "standard": {
-    "env": [
-      "jest"
-    ],
-    "parser": "@babel/eslint-parser"
+    "node": ">=20.6.0"
   }
 }