Filters are now separate structures to include a product or not based
on their own set of properties. For now, include and exclude filters
are supported. They take a regex as an argument and include a product
if the regex matches (or doesn't match) the product name. This commit
will allow us to create new filters on product like on a price range.
Signed-off-by: Julien Riou <julien@riou.xyz>
