Feature Request: Option to pass Puppeteer executable path

[mabc224]

We should be able to pass Puppeteer executable path in browser config.
Currently, We can pass custom_func but it does not support option of executable path inside.
After this, We will be able to run it in AWS Lambda function.

let browser_config = {
    executablePath: '/path/to/Chrome',
}

We may need to change in these file to support executablePath
https://github.com/NikolaiT/se-scraper/blob/master/examples/pluggable.js#L3
https://github.com/NikolaiT/se-scraper/blob/master/examples/pluggable.js#L49
https://github.com/NikolaiT/se-scraper/blob/master/src/node_scraper.js#L69
https://github.com/NikolaiT/se-scraper/blob/master/src/node_scraper.js#L270