Fix minor issues

- fixed indentation
- moved navbars and policy popup to "partials"
- fixed broken image if website icon wasn't set

partials/navbar-primary.hbs

@@ -0,0 +1,8 @@
+<nav id="mind-global-navbar_primary" class="mind-global-navbar_primary unselectable">
+    <a href="/">
+        {{#if @site.icon}}
+            <img src="{{img_url @site.icon size="xxs"}}"  alt="Website Logo"/>
+        {{/if}}
+    </a>
+    {{navigation}}
+</nav>

partials/navbar-secondary.hbs

@@ -0,0 +1,3 @@
+<nav class="mind-global-navbar_secondary unselectable">
+    {{navigation type="secondary"}}
+</nav>

partials/policy-popup.hbs

@@ -0,0 +1,8 @@
+<div class="mind-policy-popup" id="mind-policy-popup">
+    <h4>This website uses cookies.</h4>
+    <p>We use cookies to ensure you the best experience.
+        <br>
+        By visiting our website, you agree with our <a href="/policy" target="_blank">Privacy Policy</a>.
+    </p>
+    <button onclick="agreePolicyPopup()">Ok, understood</button>
+</div>

partials/post-card-big.hbs

@@ -1,6 +1,6 @@
 <article class="{{post_class}}">
   <a class="mind-post-card-big_main" href="{{url}}">
-    <img class="mind-post-card-big_feature-image" src="{{img_url feature_image size="m"}}" />
+    <img class="mind-post-card-big_feature-image" src="{{img_url feature_image size="m"}}"  alt="Feature Image"/>
     <header class="mind-post-card-big_header">
       <p class="mind-post-card-big_meta"><span class="mind-post-card-big_tag">{{primary_tag.name}}</span>
         • <time class="post-date" datetime="{{date format='YYYY-MM-DD'}}">{{date format="DD MMMM YYYY"}}</time></p>

partials/posts-card-small.hbs

@@ -3,7 +3,7 @@
   {{#foreach related}}
     <article class="{{post_class}}">
       <a class="mind-post-card-sidebar_main" href="{{url}}">
-        <img class="mind-post-card-sidebar_feature-image" src="{{img_url feature_image size="s"}}" />
+        <img class="mind-post-card-sidebar_feature-image" src="{{img_url feature_image size="s"}}"  alt="Feature Image"/>
         <header class="mind-post-card-sidebar_header">
           <p class="mind-post-card-sidebar_meta"><span class="mind-post-card-sidebar_tag">{{primary_tag.name}}</span> • <time class="post-date" datetime="{{date format='YYYY-MM-DD'}}">{{date format="DD MMMM YYYY"}}</time></p>
           <h5>{{title}}</h5>

partials/tag-card-big.hbs

@@ -1,6 +1,6 @@
 <article class="{{post_class}}">
   <a class="mind-tag-card_main" href="{{url}}">
-    <img class="mind-tag-card_feature-image" src="{{img_url feature_image size="s"}}" />
+    <img class="mind-tag-card_feature-image" src="{{img_url feature_image size="s"}}"  alt="Feature Image"/>
     <header class="mind-tag-card_header">
       <h4>{{name}}</h4>
     </header>