Replace icons in Boards vue components

app/assets/javascripts/boards/components/modal/list.vue

 <script>
+  import Icon from '~/vue_shared/components/icon.vue';
   import bp from '../../../breakpoints';
   import ModalStore from '../../stores/modal_store';
   import IssueCardInner from '../issue_card_inner.vue';
@@ -6,6 +7,7 @@
   export default {
     components: {
       IssueCardInner,
+      Icon,
     },
     props: {
       issueLinkBase: {
@@ -147,13 +149,13 @@
             :issue="issue"
             :issue-link-base="issueLinkBase"
             :root-path="rootPath"/>
-          <span
+          <icon
             v-if="issue.selected"
             :aria-label="'Issue #' + issue.id + ' selected'"
+            name="mobile-issue-close"
             aria-checked="true"
-            class="issue-card-selected text-center">
-            <i class="fa fa-check"></i>
-          </span>
+            class="issue-card-selected text-center"
+          />
         </div>
       </div>
     </div>

app/assets/javascripts/boards/components/modal/lists_dropdown.vue

 <script>
 import { Link } from '@gitlab-org/gitlab-ui';
+import Icon from '~/vue_shared/components/icon.vue';
 import ModalStore from '../../stores/modal_store';
 import boardsStore from '../../stores/boards_store';
 
 export default {
   components: {
     'gl-link': Link,
+    Icon,
   },
   data() {
     return {
@@ -35,7 +37,9 @@ export default {
         class="dropdown-label-box">
       </span>
       {{ selected.title }}
-      <i class="fa fa-chevron-down"></i>
+      <icon
+        name="angle-down"
+      />
     </button>
     <div class="dropdown-menu dropdown-menu-selectable dropdown-menu-drop-up">
       <ul>

app/assets/stylesheets/framework/dropdowns.scss

@@ -144,6 +144,13 @@
     top: 11px;
     right: 8px;
   }
+
+  .ic-angle-down {
+    position: absolute;
+    top: 8px;
+    right: 8px;
+    color: $gray-darkest;
+  }
 }
 
 @mixin dropdown-item-hover {