New Server API to manage scripts

[lvca]

A nice feature of OrientDB was having persistent scripts that work like stored procedures.

While having it in the database could be very helpful, editing scripts through OrientDB Studio is not the most developer-friendly thing I've seen.

I like the approach of having scripts stored in the file system, so you can use your favorite IDE. Some developers built a simple component that loads the scripts at startup and refreshes the scripts when they are changed. We should provide a component that does that.

The component should also be accessible through API (create, read, update, and delete scripts) and be integrated in Studio as well.

[lvca]

This issue replaces #700.