Implement a Go-Lab integrated App Selection feature

[zstars]

As of now, to translate an app (or actually to adapt it) you need to write the URL for its XML.

To make this process more user-friendly, we should contact a remote service in GoLab to retrieve the list of apps, the names, URLs, etc, and let the user choose from them through some kind of DropDown list.

As of now that remote service does not exist (or is significantly cumbersome to use) but one will be implemented in the future.

The translator should be prepared for it.

[zstars]

Should use the Web Service: http://www.golabz.eu/rest/apps/retrieve.json