Removes analytics_property setting from theme

** Why are these changes being introduced:

* Initially I was thinking that the analytics property ID would be a
  configurable value for each site, so I'd built a settings field for
  that value. However, we've since clarified that this will not be
  optional, or configurable.

** Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/post-36

** How does this address that need:

* This removes the analytics_property settings field from the theme,
  including how it was passed to the FooterHelper as an example of a
  string to be processed. The FooterHelper itself is being removed in
  a parallel PR to this one, so I'm leaving it in the footer.

** Document any side effects to this change:

* None, hopefully.

Author: matt-bernhardt

config/theme.ini

@@ -10,11 +10,6 @@ omeka_version_constraint = "^4.0.0"
 helpers[] = "FooterHelper"
 
 [config]
-elements.analytics_property.name = "analytics_property"
-elements.analytics_property.type = "Text"
-elements.analytics_property.options.label = "Analytics Property ID"
-elements.analytics_property.options.info = "This is the Matomo property ID, and can be provided by UXWS"
-
 elements.banner.name = "banner"
 elements.banner.type = "Omeka\Form\Element\Asset"
 elements.banner.options.label = "Site banner"

view/layout/layout.phtml

@@ -1,6 +1,5 @@
 <?php
 $translate = $this->plugin('translate');
-$analytics_property = $this->themeSetting('analytics_property');
 $banner_url = $this->themeSettingAssetUrl('banner');
 $banner_text = $this->themeSetting('banner_text');
 
@@ -98,7 +97,7 @@ $userBar = $this->userBar();
             <?php echo $this->partial('common/footer-site-slim'); ?>
         </div>
         <footer>
-            <?php echo $this->FooterHelper($analytics_property); ?>
+            <?php echo $this->FooterHelper(''); ?>
             <span class="powered-by"><?php echo $translate('Powered by Omeka S'); ?></span>
         </footer>
     </body>