Option to not show apps already viewed in search results

**Is your feature request related to a problem? Please describe.**
As covered in #87, the search results aren't very good, which necessitates searching under multiple single and combination terms when looking for certain apps in order to ensure none are missed, which means scrolling through long lists of apps over and over again. I spent a lot of time over the past couple days searching and browsing and installing apps, and in the process I scrolled past the same apps countless times and viewed several of them multiple times as well.

**Describe the solution you'd like**
At a minimum, it would be helpful to at least have an option that apps that have been viewed (their page has been accessed) but not installed to not show up in search results until it's reset, since if the user viewed it and didn't install it, it's reasonable to assume they don't want to install it, so showing it again and again is pointless and just gets in the way. Ideally, any app that has been scrolled past (or if that's not possible, any app that was a result in a previous search) shouldn't be shown, and maybe this could be on a time limit, so any app that's been seen in the past x minutes will not be shown again.

**Describe alternatives you've considered**
Apps could be manually ignored, which could keep them from showing, but this would be a pain to do for each individual app and would take just as much time, and probably more, as it would save. The best alternative would be to improve the search, but I'm guessing that's easier said than done and will probably be a while, so as hesitant as I am to even suggest these other options, if a relatively quick band-aid fix can be done to make searching easier and less time-consuming, it would probably be worth it. Another possibility would be to at least make the search operate in an OR state rather than an AND state (and it could have a selector to switch between them) so at least instead of having to search multiple times, once for term1, once for term2, and once for term1term2, one search could be done for "term1 term2 term1term2" which would show any apps that match any one of the search terms.