feat: Use ES modules in src

[GrosSacASac]

todo still:
some tests use dynamic require

[tunnckoCore]

Never liked named exports. It's useful, this here is great example for cases when should not be used.

Better os and path to remain.

[GrosSacASac]

should I replace
import { tmpdir } from 'os';
with
import os from 'os';
?

[GrosSacASac]

I used the automatic vscode conversion initially

[GrosSacASac]

test/unit/persistent-file.test.js
The module factory of jest.mock() is not allowed to reference any out-of-scope variables.
Invalid variable access: jest
Allowed objects: AbortController, AbortSignal, AggregateError, Array, ArrayBuffer, Atomics, BigInt, BigInt64Array, BigUint64Array, Boolean, Buffer, DataView, Date, Error, EvalError, Event, EventTarget, FinalizationRegistry, Float32Array, Float64Array, Function, Generator, GeneratorFunction, Infinity, Int16Array, Int32Array, Int8Array, InternalError, Intl, JSON, Map, Math, MessageChannel, MessageEvent, MessagePort, NaN, Number, Object, Promise, Proxy, RangeError, ReferenceError, Reflect, RegExp, Set, SharedArrayBuffer,
String, Symbol, SyntaxError, TextDecoder, TextEncoder, TypeError, URIError, URL, URLSearchParams, Uint16Array, Uint32Array, Uint8Array, Uint8ClampedArray, WeakMap, WeakRef, WeakSet, WebAssembly, arguments, clearImmediate, clearInterval, clearTimeout, console, decodeURI, decodeURIComponent, encodeURI, encodeURIComponent, escape, eval, expect, global,
globalThis, isFinite, isNaN, jest, parseFloat, parseInt, process, queueMicrotask, require, setImmediate, setInterval, setTimeout, undefined, unescape.
Note: This is a precaution to guard against uninitialized mock variables. If it is ensured that the mock is required lazily, variable names prefixed with mock (case insensitive) are permitted.

  15 |
  16 | jest.mock('fs', () => {
> 17 |   const fs = jest.requireActual('fs');
     |              ^^^^
  18 |   return {
  19 |     ...fs,
  20 |     unlink: jest.fn(),

looking for a jest expert for this one