Add more sorting options to patch views

[nephros]

As discussed in PR #44, it would be nice to have more sorting options available for the patch lists.

Quoting @Olf0 in #44 (comment)_

Ideas for sorting options

• Web catalog
  • By name (alphabetically)
  • By categories (alphabetically) and then (in each category) by name (alphabetically)
  • By stars
  • By downloads
  • [While I am not yet fully convinced that the following are really helpful, you both seem to be]
    • In the weird "unordered" order the web-catalog's web-service sorts them
    • By modification time (i.e., "last updated")
    • By author (alphabetically) and then (for each author) by name (alphabetically)
    • By creation time (i.e., when its first version was uploaded to the web-catalog).
    • By "installed / not installed"
• List of installed patches
  • By name (alphabetically)
  • By categories (alphabetically, followed by the extra category "RPM patches") and then (in each category) by name (alphabetically)
  • [While I am not yet fully convinced that the following are really helpful, you both seem to be]
    • By the order in which they are applied (see issue 35); i.e., the status quo. Initially this is also the order in which they were installed, until one reorders them manually.
    • By modification time (i.e., "last updated"; do RPMs have an internal time-stamp, which can be queried per rpm utility (IIRC, yes)?)
    • By author (alphabetically) and then (for each author) by name (alphabetically)
    • By creation time (i.e., when its first version was uploaded, but that is not applicable for RPM patches or one would have to query Openrepos, but an RPM-patch could also be from somewhere else).
    • By stars (not for RPMs, or one would have to query Openrepos, but an RPM-patch could also be from somewhere else).
    • By downloads (not for RPMs, or one would have to query Openrepos, but an RPM-patch could also be from somewhere else).

Actually it would be nice to be able to apply multiple sorting criteria at once, but I have no idea how a usable UI for that may look like.
This is why I tried to communicate, to evaluate what is really neded and to set priorities. But maybe there is a way to handle all sensible sorting options in a feasible manner.

P.S.: And I believe the default order should be simply and strictly "by name" (i.e., without taking categories or anything else into account).