CRAVEX: Web UI: Extend to work per app/product

[pombredanne]

Extend the web UI to work on the packages of a product, reusing extra product-level package flags (such as purpose and modification), global- and product policy.

[tdruez]

PR #173 introduces a new "Vulnerabilities" tab in the Product details view, listing all vulnerabilities of a Product. With the ability to filter and sort by score.
Note that the tab is displayed but disabled if no vulnerabilities are found for the Product.

[pombredanne]

This is looking great. Closing. Thanks!