FEATURE: add period filter in top topics route for tags. (#13415)

And also move all the "top topics by period" routes to query string param.

/top/monthly => /top?period=monthly
/c/:slug/:id/l/top/monthly => /c/:slug/:id/l/top?period=monthly
/tag/:slug/l/top/daily => /tag/:slug/l/top?period=daily (new)

spec/requests/list_controller_spec.rb

@@ -412,7 +412,7 @@ RSpec.describe ListController do
 
     TopTopic.periods.each do |period|
       it "renders #{period} top RSS" do
-        get "/top/#{period}.rss"
+        get "/top.rss?period=#{period}"
         expect(response.status).to eq(200)
         expect(response.media_type).to eq('application/rss+xml')
       end