FEATURE: navigate to first post and auto bump category settings

### navigate_to_first_post_after_read setting for categories

When enabled on categories logged on users will return to OP after
reading the entire category. (useful for documentation categories)

### num_auto_bump_daily

Set a number of topics that will automatically bump daily on a category.

- Every 15 minutes we will check if any category has this setting
- Categories with the setting are shuffled
- We exclude pinned, closed, category description and archived topics
- Maximum of 1 topic for the list of categories is bumped till limit reached per category
- We always try to bump oldest first
- Limit is elastic using a RateLimiter that ensures that we only bump N per day

Also some minor organisation on category settings

Froze strings on category.rb

app/assets/stylesheets/common/base/modal.scss

@@ -369,12 +369,8 @@
 }
 
 .edit-category-modal {
-  .future-date-input,
-  .num-featured-topics-fields,
-  .position-fields {
-    input[type="text"] {
-      width: 50px;
-    }
+  input[type="number"] {
+    width: 50px;
   }
 
   .subcategory-list-style-field {