This commit moves all files previously under the 'app' bundle in
the Django pipeline to being compiled by webpack under the 'app'
entry point. In the process, it moves assets under the app entry
to a file called app.js that consumes all relevant css and js files.
This commit also edits the webpack config to be able to expose certain
variables for third party libraries that are currently required by
some modules. This is bad coding form and should be refactored to
requiring whatever dependencies a module may have; we're just
deferring that to the future to simplify the series of transitions we
need to do here. The variable exposure is done using expose-loader in
webpack.
The app/index.html template is edited to override the newly introduced
'commonjs' block in the base template. This is done as a temporary
measure so as not to disrupt other pages on the app during the transition.
It also fixes the value of the 'this' context that was being inferred
as window by third party libraries. This is done using imports-loader
in the webpack config. This is also messy and probably isn't how we
want things to work long term.