Enhance Rendertron config

[gravi2]

This PR enhances the config options exposed/available to rendertron. It adds the following config options in addition to the existing 'datastoreCache' option

timeout: number;
port: string;
width: number;
height: number;

Respective default values are also been added:

datastoreCache: false,
timeout: 10000,
port: '3000',
width: 1000,
height: 1000,

This PR helps address following open issues:

1. page.setViewport() to 1280x768 #213 , Pass resolution to 'render' #184 (Allow setting viewport/resolution)
2. timeout option in rendertron middleware doesn't do anything #160, Change renderbudget timeouts #211 (Allow setting timeout)
3. How to specify port #253 ( Specify port in config )

Also includes following Improvements:

1. npm run monitor and monitor-inspect will now listen for any src/*.ts file changes, build the rendertron.js file and reload the server. This helps for smoother development process.
2. Added nodemon.json config file to control nodemon options.
3. Added documentation in README for the new config options.

[gravi2]

@AVGP: do you have any feedback on the PR or anything I can help to get the PR merged?

[AVGP]

Hey @gravi2 - sorry for the delay and thanks for the contribution!
I'm really happy to see the config evolve and I think this PR is basically ready to be merged.

The one nit-pick I have is that I'm not sure why we need the additional dependency of ts-node - would you mind elaborating on that?

[gravi2]

@AVGP I have removed the ts-node dependency as requested. I might have added it for something but we longer seem to need it.
Also BTW I have reverted the package-lock.json file to that of master, since I see there is existing issue in master. See my comment in the issue linked below:

#281 (comment)

[AVGP]

Awesome thank you, @gravi2