Move EE differences for `app/assets/javascripts/boards/components/issue_card_inner.vue`

The file app/assets/javascripts/boards/components/issue_card_inner.vue has differences between CE and EE.

Diferences

diff --git a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/boards/components/issue_card_inner.vue b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/boards/components/issue_card_inner.vue
index 90ab3a76342..3820156e7ee 100644
--- a/home/yorickpeterse/Projects/gitlab/gdk-ce/gitlab/app/assets/javascripts/boards/components/issue_card_inner.vue
+++ b/home/yorickpeterse/Projects/gitlab/gdk-ee/gitlab/app/assets/javascripts/boards/components/issue_card_inner.vue
@@ -3,6 +3,7 @@ import { GlTooltipDirective } from '@gitlab/ui';
 import { sprintf, __ } from '~/locale';
 import Icon from '~/vue_shared/components/icon.vue';
 import TooltipOnTruncate from '~/vue_shared/components/tooltip_on_truncate.vue';
+import IssueCardWeight from 'ee/boards/components/issue_card_weight.vue';
 import UserAvatarLink from '../../vue_shared/components/user_avatar/user_avatar_link.vue';
 import eventHub from '../eventhub';
 import IssueDueDate from './issue_due_date.vue';
@@ -15,6 +16,7 @@ export default {
     UserAvatarLink,
     TooltipOnTruncate,
     IssueDueDate,
+    IssueCardWeight,
     IssueTimeEstimate,
   },
   directives: {
@@ -209,6 +211,10 @@ export default {
           <issue-due-date v-if="issue.dueDate" :date="issue.dueDate" /><issue-time-estimate
             v-if="issue.timeEstimate"
             :estimate="issue.timeEstimate"
+          /><issue-card-weight
+            v-if="issue.weight"
+            :weight="issue.weight"
+            @click="filterByWeight(issue.weight)"
           />
         </span>
       </div>

What needs to be done

1. Use async import for issue card weight component.
2. Create a mixin for EE with filterByWeight if it does not exist in CE
3. Create a mixin counterpart for CE with filterByWeight
4. Use ee_else_ce to import the mixin