Add webpack_config; document CF_TOKEN export

[limakzi]

This patch:

• Configures webpack.config in Wrangle.
• Documents CF_API_TOKEN export.

[dhaynespls]

Hey!

Good catch with the wrangler config.

You don't necessarily need the CF_API_TOKEN environment variable as you should be using https://github.com/cloudflare/wrangler#-config with an scoped token.

That said, I forgot to document that! If you could add a link to that up in section 1 that would be great.

[limakzi]

No worries. Thank you for your feedback.

• I would say, keeping the token in environment variable is a more secure way of injecting a secret than keeping that in local file-system.
• More-over, it is easier to apply for CI/CD, like we did at @sysdogs.

What do you think, @dhaynespls ?

[dhaynespls]

That's fair, we support both for a reason.

I would phrase it in a way that's something along these lines:

You will need to obtain a scoped API token to publish the worker. You can do this at https://dash.cloudflare.com/profile/api-tokens, and choose the "Edit Cloudflare Workers" template. 

To deploy with the token, 

a) wrangler config
=> enter token 
=> make deploy
b) `CF_API_TOKEN=${token}` make deploy

[limakzi]

@dhaynespls Approved the new version.
I will fix PR.

[limakzi]

Every markdown preprocessor is different, daymn!
It's sufficient, I hope. Review ready.

[dhaynespls]

Thank you!