Fixes a bug where the Foundation source strategy failed because http.rb
automatically sent a `Content-Length: 0` header with all GET requests,
which caused Foundation to return a 400 Bad Request error. This behavior
was fixed in http.rb 5.x.
http.rb 5.x has a breaking change where it now includes the request object
inside the response object, which we have to handle in a few places.
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.
* Combine MissedSearchService, PostViewCountService, and
PopularSearchService into single ReportbooruService class.
* Use Danbooru::Http for these services instead of HTTParty.