Support serving multiple different Click scripts

[fredrik-corneliusson]

At the moment click-web can only wrap and server one click script. It would be nice if it was possible to serve multiple scripts under different url paths like this.

http://myserver/script1/#
http://myserver/script2/#

Also provide an example of how to implement it.

The motivation is that some projects may have multiple main scripts and with current implementation serving them would require running multiple Flask servers on different ports and then infrastructure such as reverse proxy.