Replace app.js with webpack-dev-server

[akhenry]

Summary

Currently we provide app.js as a very basic web-server for development purposes. webpack-dev-server could do the same thing which would have multiple advantages:

• Remove any ambiguity about the purpose of app.js( app.js is not an Open MCT server, and should only be used for dev purposes.)
• Remove redundant code
• Remove a dependency on webpack-dev-middleware
• The security and familiarity of using an industry standard tool.

[unlikelyzero]

@akhenry we had that filed here: #4922 to close another issue.

I'd like to demo what we'd gain by using app.js, before moving off of it

[unlikelyzero]

@akhenry we've done quite a bit of work in the last 6 weeks on app.js. I think we should take a hard look at this.

Things to consider:

• How are we generating sourcemaps for unit and e2e tests
• How are we using NODE_ENV variables at build time and runtime? What associated functionality do we want between them?
• Why do we not demonstrate how we want folks to run this?

[scottbell]

Testing Instructions:

• Ensure npm start works for local storage
• Ensure npm start works for CouchDB

[jvigliotta]

Verified Fixed Locally - Tested with Local Storage and with CouchDB and there were no issues.

[akhenry]

Verified fixed.