Build & slew of minor improvements

[Marc-Andre-Rivet]

• the dev build was useful before we used external source maps on the prod build -- prod and dev are now redundant as the source map is always available
• use package-info.json in the dash_core_components/ dist folder to allow normal npm publish to work (like in table)
• whitelisting npm publish content through files in package.json instead of blacklisting through .gitgnore / .npmignore (like in table)
• get version information from package-info.json and package.json (setup.py) instead of version.py (like in table)
• resolve setup.py content from package.json (like in table)
• clean up the build commands & always build r and python components
• removing old artefacts & dev artefacts

Tagging @rpkyle as this may impact the R generation in ways I don't understand :)

[alexcjohnson]

Do we use the copied package[-info].json for anything besides the version info? If so, can we just stop copying it, and instead have the component generation step create a version.py matching the package.json version?

For now since we already have this pattern in table, fine to expand it. But perhaps with dash-component-system we simplify this to an auto-generated version.py.

[Marc-Andre-Rivet]

Agreed. I kept it because my understanding was that R uses it. @rpkyle?

[alexcjohnson]

I kept it because my understanding was that R uses it.

AFAICT R only uses the base package.json

https://github.com/plotly/dash/blob/ec1576c3652cbb90ffb064abe2753a17e13f3c51/dash/development/component_generator.py#L97-L102

[alexcjohnson]

💃 Nicely done 💣

[Marc-Andre-Rivet]

@alexcjohnson Actual back on your comment

Do we use the copied package[-info].json for anything besides the version info?

We do not, the only other usage is done with the root package.json here -- will update to generate version.py and update the table as well.

Update on will update to generate version.py and update the table as well -- this involves updating the component generator. In the end, will do this in a followup step.