Update tooling

[Dan-Shields]

• Moves away from deprecated/unsupported versions of various libraries.
• Removes a bunch of unnecessary dependencies and scripting left over from the initial template.
• Configures babel for only the versions of chromium we care about.
• Applies eslint's recommended rules, while trying to keep the same code style as before.

React version is unchanged as its still supported and would require way too much work to be worth it.

If you're wondering why, I'm planning to use this plugin as a basis for an in-house extension at work, and before I get started it'll be nice to have more up-to-date foundations.

EDIT: This will drop support for Node 8 and earlier when developing.

[Dan-Shields]

Also something I've tried and seems to work well is changing the ExtendScript .jsx files to .jsxinc. This doesn't change the functionality whatsoever, but makes it more clear whether a file is ExtendScript, or a react JSX file. It's minor so not committed yet, but I'd be interested in your thoughts @bodymovin

[bodymovin]

hey thanks so much for all the improvements!!
I'm trying the branch locally to make sure everything is working fine.
As soon as it's ready, I'll merge everything.
Please don't update the PR for now so I don't have to review it all over again :)
Regarding the file renaming, it makes sense. I think it can be done in another PR.

[Dan-Shields]

Sounds great, let me know if you find anything that you think needs changing!
Sorry if I made you restart the review, I had some uncommitted changes but everything's there now 👌

[bodymovin]

I did a build and it didn't work. I'll have to look into it, but has it worked for you?

[Dan-Shields]

I did a build and it didn't work. I'll have to look into it, but has it worked for you?

Apologies, I didn't properly test the prod build since changing the webpack config, public path needed to be set differently. I've updated it and tested and it seems to be working now :)