Decrease the HTTP timeout to 0.5 seconds when fetching popular tags from
Reportbooru. Increase the length of time that popular tags are cached
from 1 minute to 1 hour. This is for the list of popular searches in the
front page sidebar.
Revert back to previous workaround of fetching previous day if current
day returns no result. A terrible hack, really we should convert dates
to Reportbooru's timezone, but that has other complications.
Fix the sidebar on the /posts index page sometimes being blank. This
could happen when either the related tag calculation was too slow and
timed out, or when Reporbooru was unavailable and we couldn't fetch the
list of popular tags.
In the tag list would otherwise be blank, we fall back to frequent tags
(the most common tags on the current page of results).
Also change it so that if Reportbooru is unconfigured, we fail
gracefully by returning blank results instead of failing with an
exception. This is so we can still view the popular searches and missed
searches pages during testing (even though they'll be blank).
* Combine MissedSearchService, PostViewCountService, and
PopularSearchService into single ReportbooruService class.
* Use Danbooru::Http for these services instead of HTTParty.
