CE Improve import status table UI

What does this MR do?

EE: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8707

Improve import status table UI, replace with vue app.

• Add "Go to project" button
• Align import buttons to the right
• Remove namespace select grey container
• Removing row status colour and use ci-style status icons to represent status

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14010

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides

app/assets/javascripts/import/components/import.vue

 <script>
-  import { mapActions, mapState } from 'vuex';
+  import { mapActions, mapState, mapGetters } from 'vuex';
   import ImportedProjectTableRow from './imported_project_table_row.vue';
   import ProviderRepoTableRow from './provider_repo_table_row.vue';
+  import simplePoll from '../../lib/utils/simple_poll';
+  import LoadingButton from '../../vue_shared/components/loading_button.vue';
+  import eventHub from '../event_hub';
 
   export default {
     name: 'Import',
@@ -9,6 +12,7 @@
     components: {
       ImportedProjectTableRow,
       ProviderRepoTableRow,
+      LoadingButton,
     },
 
     props: {
@@ -19,18 +23,23 @@
     },
 
     computed: {
-      ...mapState(['importedProjects', 'providerRepos', 'isLoadingRepos'])
+      ...mapState(['importedProjects', 'providerRepos', 'isLoadingRepos']),
+      ...mapGetters(['isLoadingAnyImport']),
     },
 
     mounted() {
-      this.fetchRepos();
+      return this.fetchRepos().then(this.pollJobs);
     },
 
     methods: {
-      ...mapActions(['fetchRepos']),
+      ...mapActions(['fetchRepos', 'fetchJobs']),
 
       importAll() {
-        console.log('import all');
+        eventHub.$emit('importAll');
+      },
+
+      pollJobs() {
+        return simplePoll((continuePolling) => this.fetchJobs().then(() => continuePolling()), 3000, Infinity)
       },
     },
   }
@@ -42,13 +51,12 @@
       <p class="light text-nowrap mt-2 my-sm-0">
         {{ s__('Import|Select the projects you want to import') }} 
       </p>
-      <button
+      <loading-button
+        :loading="isLoadingAnyImport"
+        :label="s__('Import|Import all repositories')"
         type="button"
-        class="btn btn-success"
         @click="importAll"
-      >
-        {{ s__('Import|Import all repositories') }}
-      </button>
+      />
     </div>
     <gl-loading-icon
       v-if="isLoadingRepos"