rules: add support for other content

It is now possible to handle other contents such as IP reputation
file. The source created is copied to the rules directory. Its name
is the one of the source.

This patch implements the backend and a basic working interface for
user. More to come on that.
rules: handle other content source in view

Don't display categories array as there is none in this type
of content.
rules: add warning on name selection

When user choose 'other content', he must know that the name will
be used to store the file in the generated ruleset. We use JS to
display a div with a warning text when the datatype is 'Other content'.
rules: switch version to 0.7