cloudflare: fix purging of cached urls.

* Switch CloudflareService from HttpartyCache to Danbooru::Http.

* Purge cached urls from Cloudflare when a post is replaced and the md5
  doesn't change. This happens when a corrupted image is replaced or
  thumbnails are regenerated. Before we purged urls when a post was
  expunged, which was unneeded because those urls can expire naturally.
  It was also wrong because the subdomains were hardcoded, the urls used
  http:// instead of https://, and we didn't account for tagged urls.

app/logical/danbooru/http.rb

@@ -3,7 +3,7 @@ module Danbooru
     attr_accessor :cache, :http
 
     class << self
-      delegate :get, :post, :cache, :auth, :basic_auth, :headers, to: :new
+      delegate :get, :post, :delete, :cache, :auth, :basic_auth, :headers, to: :new
     end
 
     def get(url, **options)
@@ -14,6 +14,10 @@ module Danbooru
       request(:post, url, **options)
     end
 
+    def delete(url, **options)
+      request(:delete, url, **options)
+    end
+
     def cache(expiry)
       dup.tap { |o| o.cache = expiry.to_i }
     end
@@ -41,7 +45,7 @@ module Danbooru
     end
 
     def cached_request(method, url, **options)
-      key = Cache.hash({ method: method, url: url, **options }.to_json)
+      key = Cache.hash({ method: method, url: url, headers: http.default_options.headers.to_h, **options }.to_json)
 
       cached_response = Cache.get(key, @cache) do
         response = raw_request(method, url, **options)