Replace more icons with SVG, repo search tweaks (#13860)

* Replace more icons with SVG

- Replace remaining icons on admin page with SVG
- Fix vertical menu background on arc-green
- Minor improvments to frontpage repo search
- More icon replacements here and there

* fix integration

* whitespace tweak

* add comment

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

templates/admin/org/list.tmpl

@@ -45,7 +45,7 @@
 							<td>{{.NumMembers}}</td>
 							<td>{{.NumRepos}}</td>
 							<td><span title="{{.CreatedUnix.FormatLong}}">{{.CreatedUnix.FormatShort}}</span></td>
-							<td><a href="{{AppSubUrl}}/org/{{.Name}}/settings"><i class="fa fa-pencil-square-o"></i></a></td>
+							<td><a href="{{AppSubUrl}}/org/{{.Name}}/settings">{{svg "octicon-pencil"}}</a></td>
 						</tr>
 					{{end}}
 				</tbody>