Move library and npm package generator from workspace to js plugin

[Elyahou]

Hello,

I see that the nx @nwl/workspace plugin include generator for typescript libraries or npm packages.

I think that these generators should be only available in @nrwl/js plugin and not in the workspace plugin, that should only contain core nx features that are not related to specific languages.

It will by the way remove jest or eslint dependencies from the workspace plugin, that make more sense since when needing only core nx features we don't need these packages.