Source-maps not generated when dash-renderer bundle is created

[HammadTheOne]

As a continuation of #1611 (comment), the ONLY case we're generating a sourcemap now is when you run webpack-serve (which is what you get with npm start). The other build commands now seem to be all the same (as far as the bundle itself is concerned) and create no sourcemap. npm run build:js and build:dev are now literally the same command.

Some discussion might be required to determine if this was an intentional change with the tooling updates in #1576, or if this is something we need to address.

[gvwilson]

@HammadTheOne is this still a concern?

[HammadTheOne]

We can close this for now.