Fetch dependencies from npm

[TimKam]

Instead of pointing to CDNs for the JavaScript dependencies, install them via NPM. For now, don't set up a "full" build (webpack or similar) to avoid the overhead that comes with it.

[cleberjamaral]

Hi Timotheus,
I have started this job in the branch "testjs". The original idea was adding tests on the client-side. After many issues, I realised that first, it would be necessary to restructure the javascript code. In this branch the js source is in /src/js, using "./gradlew build" it generates in /src/resources/js the bundle file jacamoweb.js. (currently occupying 44kB). Please, have a look, you will probably find many issues and ways to improve the way I am proposing.
Cheers

[TimKam]

I think generally, it makes sense. I will checkout the branch and see what else we need to do to get this fully working.

[TimKam]

Some notes:

• I needed to run npm install -g webpack && npm webpack-cli to make the build work. This should be handled by the built script.
• Currently, the build result is checked in (should be ignored).
• The dependencies are still included in the HTML files.
• The gradle run task does not compile changes made to the JavaScript source files.