Angular cli readme instructions

[TomDemulierChevret]

Features, Bug fixes, and others:

This pull request add instructions on how to use plotly.js in an Angular application built with Angular CLI.

[etpinard]

Thanks for the info.

My only concern is this might make the README too long. Perhaps we could wrap this info in a <details> block?

[TomDemulierChevret]

Or maybe merge the whole Modules section with dist/README.md into a file dedicated to building & bundling the library ?

The locales section of dist/README.md would need an update too, since setup described works only if you include plotly.js as a global script.
Plus, it doesn't allow the user to customise the locales (which is really easy if you include locale data in more modular maner).

[alexcjohnson]

Or maybe merge the whole Modules section with dist/README.md into a file dedicated to building & bundling the library ?

I like the idea of pulling build info out into a separate file. I'd leave dist/README.md as it is, since it's all about the pre-built, ready-to-use files, and I'd leave the note/link about partial bundles in the main readme (might even reorganize to bring that and the CDN links a little higher up, but that's a separate issue). But a separate file on making custom builds and using them with various pipelines would be great, then we can go into all necessary details without getting people bogged down while they're perusing the top-level readme. How about just /BUILDING.md?

[etpinard]

I also would prefer leaving this new piece of document out of dist/README.md.

Personally, I'd vote for putting in the root REAMDE.md under a new section called Building or Bundling possibly using <details>.

[fhurta]

Just a note to the sample - as scatter is included in core, maybe there could be some other sample (or the extra line removed).

"compilerOptions": {
    "paths": {
        "plotly.js": [
            "../node_modules/plotly.js/lib/core.js",
            "../node_modules/plotly.js/lib/scatter.js"
        ]
    }
}

[etpinard]

done in #2654