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/javascripts/discourse/models/category.js.es6

@@ -115,7 +115,10 @@ const Category = RestModel.extend({
         default_view: this.get("default_view"),
         subcategory_list_style: this.get("subcategory_list_style"),
         default_top_period: this.get("default_top_period"),
-        minimum_required_tags: this.get("minimum_required_tags")
+        minimum_required_tags: this.get("minimum_required_tags"),
+        navigate_to_first_post_after_read: this.get(
+          "navigate_to_first_post_after_read"
+        )
       },
       type: id ? "PUT" : "POST"
     });

app/assets/javascripts/discourse/models/topic.js.es6

@@ -212,11 +212,18 @@ const Topic = RestModel.extend({
   }.property("url", "last_read_post_number"),
 
   lastUnreadUrl: function() {
-    const postNumber = Math.min(
-      this.get("last_read_post_number") + 1,
-      this.get("highest_post_number")
-    );
-    return this.urlForPostNumber(postNumber);
+    const highest = this.get("highest_post_number");
+    const lastRead = this.get("last_read_post_number");
+
+    if (highest <= lastRead) {
+      if (this.get("category.navigate_to_first_post_after_read")) {
+        return this.urlForPostNumber(1);
+      } else {
+        return this.urlForPostNumber(lastRead + 1);
+      }
+    } else {
+      return this.urlForPostNumber(lastRead + 1);
+    }
   }.property("url", "last_read_post_number", "highest_post_number"),
 
   lastPostUrl: function() {

app/assets/javascripts/discourse/templates/components/edit-category-settings.hbs

@@ -1,3 +1,19 @@
+{{#if showPositionInput}}
+  <section class='field position-fields'>
+    <label>
+      {{i18n 'category.position'}}
+      {{text-field value=category.position class="position-input" type="number"}}
+    </label>
+  </section>
+{{/if}}
+
+{{#unless showPositionInput}}
+  <section class='field'>
+    {{i18n 'category.position_disabled'}}
+    <a href="/admin/site_settings/category/basic">{{i18n 'category.position_disabled_click'}}</a>
+  </section>
+{{/unless}}
+
 <section class='field'>
   <div class="control-group">
     <label>
@@ -74,14 +90,21 @@
     </div>
 </section>
 
-<section class="field num-featured-topics-fields">
+<section class="field">
   <label>
     {{#if category.parent_category_id}}
       {{i18n "category.subcategory_num_featured_topics"}}
     {{else}}
       {{i18n "category.num_featured_topics"}}
     {{/if}}
-    {{text-field value=category.num_featured_topics}}
+    {{text-field value=category.num_featured_topics type="number"}}
+  </label>
+</section>
+
+<section class="field">
+  <label>
+    {{i18n "category.num_auto_bump_daily"}}
+    {{text-field value=category.custom_fields.num_auto_bump_daily type="number"}}
   </label>
 </section>
 
@@ -92,6 +115,13 @@
   </label>
 </section>
 
+<section class="field">
+  <label>
+    {{input type="checkbox" checked=category.navigate_to_first_post_after_read}}
+    {{i18n "category.navigate_to_first_post_after_read"}}
+  </label>
+</section>
+
 {{#if siteSettings.topic_featured_link_enabled}}
   <section class='field'>
     <div class="allowed-topic-featured-link-category">
@@ -129,29 +159,6 @@
   {{plugin-outlet name="category-email-in" args=(hash category=category)}}
 {{/if}}
 
-{{#if showPositionInput}}
-  <section class='field position-fields'>
-    <label>
-      {{i18n 'category.position'}}
-      {{text-field value=category.position class="position-input"}}
-    </label>
-  </section>
-{{/if}}
-
-{{#unless emailInEnabled}}
-  <section class='field'>
-    {{i18n 'category.email_in_disabled'}}
-    <a href="/admin/site_settings/category/email">{{i18n 'category.email_in_disabled_click'}}</a>
-  </section>
-{{/unless}}
-
-{{#unless showPositionInput}}
-  <section class='field'>
-    {{i18n 'category.position_disabled'}}
-    <a href="/admin/site_settings/category/basic">{{i18n 'category.position_disabled_click'}}</a>
-  </section>
-{{/unless}}
-
 {{#if siteSettings.tagging_enabled}}
   <section class='field minimum-required-tags'>
     <label>
@@ -176,3 +183,10 @@
 </section>
 
 {{plugin-outlet name="category-custom-settings" args=(hash category=category)}}
+
+{{#unless emailInEnabled}}
+  <section class='field'>
+    {{i18n 'category.email_in_disabled'}}
+    <a href="/admin/site_settings/category/email">{{i18n 'category.email_in_disabled_click'}}</a>
+  </section>
+{{/unless}}

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 {