Assets #868

[byronz]

this PR targets to clean the legacy dash-renderer assets present in git source repo. it closes #868
a new entry-point CLI tool is introduced as renderer, it has two jobs: npm and bundles.

[alexcjohnson]

Suggested change

	After Dash 1.2, The renderer bundle and its peer dependencies can be packed and generated from the source code. The only version of the truth is defined in `dash-renderer\package.json` file. A build tool `renderer`, which is a tiny Python script defined as a Dash entry point, has few commands like:
	As of Dash 1.2, The renderer bundle and its peer dependencies can be packed and generated from the source code. Dependency files are no longer included in this repository, they are downloaded when needed based on the versions listed in `dash-renderer/package.json`. A build tool `renderer`, which is a tiny Python script installed by Dash as a command-line tool, has a few commands:

[alexcjohnson]

Suggested change

	1. `renderer npm` installs all the npm modules using this `package.json` files. Note that the `package-lock.json` file is the computed reference product for the versions defined with tilde(~) or caret(^) syntax in **npm**
	1. `renderer npm` installs all the npm modules using this `package.json` files. Note that the `package-lock.json` file is the computed reference product for the versions defined with tilde(~) or caret(^) syntax in **npm**. This is called by `npm run build`, or you can also call it directly if you add or update a dependency module.

[byronz]

it's slightly safer for people not family with js to call with renderer as it will handle the location with os.chdir().

[alexcjohnson]

Good point - I just wanted to give people some idea when to use each of these commands. So perhaps:

Call this if you add or update a dependency module. npm run build calls this and renderer bundle, but you can only call it from the dash-renderer directory.

?

[alexcjohnson]

Suggested change

	2. `renderer bundles` parses the locked version JSON, copies all the peer dependencies into dash_renderer folder, bundles the renderer assets, and generates an `__init__.py` to map all the resources
	2. `renderer bundles` parses the locked version JSON, copies all the peer dependencies into dash_renderer folder, bundles the renderer assets, and generates an `__init__.py` to map all the resources. This is called by `npm run build`, or you can call it directly if the renderer code has changed.

[alexcjohnson]

What should we say about when to use this? Just that we use it internally to test that the build has not changed?

[byronz]

yes, something the assets bundle check
I extracted this out as a single job, so we can reuse it when we want to do some simple compare from the hash

[alexcjohnson]

FWIW I think I generally prefer links inline like this, but it did work the way it was, with the link defined at the end of the doc.

[alexcjohnson]

💃