Use streaming to avoid string size limitations

[Bluscream]

https://stackoverflow.com/questions/44533966/v8-node-js-increase-max-allowed-string-length

PS C:\Users\blusc\AppData\Local\Temp\psdetest\har2openapi> npm run examples

> har2openapi@1.0.0 examples
> node index.js examples input/har1.json input/har2.json input/har3.json

node:fs:441
    return binding.readFileUtf8(path, stringToFlags(options.flag));
                   ^

Error: Cannot create a string longer than 0x1fffffe8 characters
    at readFileSync (node:fs:441:20)
    at parseHarFile (C:\Users\blusc\AppData\Local\Temp\psdetest\har2openapi\lib.js:594:40)
    at C:\Users\blusc\AppData\Local\Temp\psdetest\har2openapi\lib.js:406:54
    at Array.map (<anonymous>)
    at generateSpec (C:\Users\blusc\AppData\Local\Temp\psdetest\har2openapi\lib.js:406:38)
    at Object.<anonymous> (C:\Users\blusc\AppData\Local\Temp\psdetest\har2openapi\index.js:30:36)
    at Module._compile (node:internal/modules/cjs/loader:1546:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1691:10)
    at Module.load (node:internal/modules/cjs/loader:1317:32)
    at Module._load (node:internal/modules/cjs/loader:1127:12) {
  code: 'ERR_STRING_TOO_LONG'
}

Node.js v22.6.0