Allow sorting by name, average rating or number of reviews

[ewangi]

Currently the software packages in the Software Manager categories are ordered, roughly speaking, by the number of reviews (rating might also be a factor as this order is not set in stone - for example, the System Tools category currently lists the packages in the order 238 reviews, 165, 160, 207, 174, etc.).

For reasons of flexibility and control, it could be useful to add header buttons to also allow the user to order the packages alphabetically (ascending), by rating (descending), or by the number of reviews (descending).

[xenopeek]

Packages are currently sorted by their points first, name second. Points are calculated as the sum of the review score minus 3 of each review (e.g., a package with 2 reviews with score 4 and 5 would have 3 points).