Bug#908948: create an option to add dependencies as components like in node-tar

[Xavier]

Hi,

pkg-js-tools 0.8.14 adds a "add-node-component" command which updates
both gbp.conf and debian/watch

Usage:
$ add-node-component foo
$ add-node-component foo bar
$ add-node-component -g foo
$ add-node-component -g foo bar

Option "-g" tags component as "group" instead of "ignore"