Added capability to merge organisations

- Added an interface for organisation
- Added beforeDelete and beforeMerge callbacks
- Added hard/soft delete to organisations

templates/modals/organisation-merge.html.twig

@@ -0,0 +1,51 @@
+{% extends "modals/modal.html.twig" %}
+
+{% block modal_title %}{{translate("ORGANISATION.MERGE")}}{% endblock %}
+
+{% block modal_body %}
+<form class="js-form" method="POST" action="{{site.uri.public}}/api/organisations/merge">
+    {% include "forms/csrf.html.twig" %}
+    <input type="hidden" name="source_slug" value="{{organisation.slug}}">
+    <div class="js-form-alerts">
+    </div>
+    <div class="js-form-organisations">
+        <h4>{{translate("ORGANISATION.MERGE_INFORM", {name: organisation.name})}}<br><small>{{translate("MERGE_CANNOT_UNDONE")}}</small></h4>
+        <div class="padding-bottom">
+            <label>{{translate("MERGE_INTO")}}:</label>
+            <select class="form-control js-select-new" type="text" name="target_slug"></select>
+        </div>
+    </div>
+    <br>
+    <div class="row">
+        <div class="col-xs-8 col-sm-4">
+            <button type="submit" class="btn btn-block btn-lg btn-success">{{translate("MERGE")}}</button>
+        </div>
+        <div class="col-xs-4 col-sm-3 pull-right">
+            <button type="button" class="btn btn-block btn-lg btn-link" data-dismiss="modal">{{translate('CANCEL')}}</button>
+        </div>
+    </div>
+</form>
+
+{# This contains a series of <script> blocks, each of which is a client-side Handlebars template.
+ # Note that these are NOT Twig templates, although the syntax is similar.  We wrap them in the `verbatim` tag,
+ # so that Twig will output them directly into the DOM instead of trying to treat them like Twig templates.
+ #
+ # These templates require handlebars-helpers.js, moment.js
+#}
+{% verbatim %}
+<script id="organisation-select-option" type="text/x-handlebars-template">
+    <div>
+        <strong>
+            {{name}}
+        </strong>
+        <br>
+        {{description}}
+    </div>
+</script>
+{% endverbatim %}
+
+<!-- Include validation rules -->
+<script>
+    {% include "pages/partials/page.js.twig" %}
+</script>
+{% endblock %}