Prepare integration of the web client into OSGi

When packaging an application as OSGi bundle with out sbt build script,
we expect directories to be organized in a certain manner. Stuffs in the
src/main/resources directory are automatically add to the jar file,
which makes it a good candidate for the client code.
Track registered web applications
Transform `blue-web` into web application

Create a simple web application that only serves static content that is
in the \BlueLaTeX webapp bundle. This application is mounted on the
'/web' URL and looks for files in the 'webapp' directory.

Remove
Adapt the web client to the new achitecture