Various design improvements (#42)

There are a couple of minor improvements which customers solve at the moment with various hacks and should be part of the theme instead.

* Removed max-width from card excerpt

* Updated custom theme settings

- Added show/hide "Read more" section in posts
- Added drop-cap option for posts
- Added show/hide metadata for posts

* Added lock icon for members-only posts on list

* Updated excerpt logic to work with access levels

* Fixing missing id's for input fields

* Updated secondary color contrast

partials/components/footer.hbs

@@ -16,7 +16,7 @@
                 Powered by <a href="https://ghost.org/" target="_blank" rel="noopener">Ghost</a>
             </div>
         </div>
-        
+
         {{#if @site.members_enabled}}
             {{#unless @member}}
                 <section class="gh-footer-signup">
@@ -26,7 +26,7 @@
                     <p class="gh-footer-signup-subhead is-body">
                         {{#if @custom.signup_subheading}}{{@custom.signup_subheading}}{{else}}{{@site.description}}{{/if}}
                     </p>
-                    {{> "email-subscription"}}
+                    {{> "email-subscription" email_field_id="footer-email"}}
                 </section>
             {{/unless}}
         {{/if}}