Rename `flags_default_topics` to `reviewable_default_topics`

This functionality regressed with the reviewable update. I took the
opporunity to rename it when fixing it for clarity.

app/assets/javascripts/discourse/widgets/hamburger-menu.js.es6

@@ -118,7 +118,9 @@ export default createWidget("hamburger-menu", {
       (this.currentUser.staff || this.currentUser.reviewable_count)
     ) {
       links.push({
-        route: "review",
+        route: siteSettings.reviewable_default_topics
+          ? "review.topics"
+          : "review",
         className: "review",
         label: "review.title",
         badgeCount: "reviewable_count",

config/locales/server.en.yml

@@ -1750,7 +1750,7 @@ en:
     auto_silence_fast_typers_on_first_post: "Automatically silence users that do not meet min_first_post_typing_time"
     auto_silence_fast_typers_max_trust_level: "Maximum trust level to auto silence fast typers"
     auto_silence_first_post_regex: "Case insensitive regex that if passed will cause first post by user to be silenced and sent to approval queue. Example: raging|a[bc]a , will cause all posts containing raging or aba or aca to be silenced on first. Only applies to first post."
-    flags_default_topics: "Show flagged topics by default in the admin section"
+    reviewable_default_topics: "Show reviewable content grouped by topic by default"
     reviewable_default_visibility: "Don't show reviewable items unless they meet this priority"
 
     reply_by_email_enabled: "Enable replying to topics via email."

config/site_settings.yml

@@ -1386,7 +1386,7 @@ spam:
   auto_silence_fast_typers_on_first_post: true
   auto_silence_fast_typers_max_trust_level: 0
   auto_silence_first_post_regex: ""
-  flags_default_topics:
+  reviewable_default_topics:
     default: false
     client: true
   reviewable_default_visibility:

db/migrate/20190508135348_rename_site_setting_default_topics.rb

@@ -0,0 +1,9 @@
+class RenameSiteSettingDefaultTopics < ActiveRecord::Migration[5.2]
+  def up
+    execute "UPDATE site_settings SET name = 'reviewable_default_topics' WHERE name = 'flags_default_topics'"
+  end
+
+  def down
+    execute "UPDATE site_settings SET name = 'flags_default_topics' WHERE name = 'reviewable_default_topics'"
+  end
+end