UI: Display last-commit header without 2nd column

This uses a CSS trick making first th to be relative block with width equal to
first two columns, effectively working around inability to use colspan="2" on
first row that was breaking "fixed-layout" for tables.

Also use grey header for last-commit SHA1 tag.

public/css/gogs.css

@@ -1859,6 +1859,11 @@ footer .container .links > *:first-child {
   padding-bottom: 5px;
   font-weight: normal;
 }
+.repository.file.list #repo-files-table thead th:first-child {
+  display: block;
+  position: relative;
+  width: 325%;
+}
 .repository.file.list #repo-files-table thead .ui.avatar {
   margin-bottom: 5px;
 }

public/less/_repository.less

@@ -146,6 +146,11 @@
 					padding-top: 8px;
 					padding-bottom: 5px;
 					font-weight: normal;
+					&:first-child {
+						display: block;
+						position: relative;
+						width: 325%;
+					}
 				}
 				.ui.avatar {
 					margin-bottom: 5px;

templates/repo/view_list.tmpl

@@ -9,10 +9,10 @@
         <img class="ui avatar image img-12" src="{{AvatarLink .LastCommit.Author.Email}}" />
         <strong>{{.LastCommit.Author.Name}}</strong>
         {{end}}
+        <a rel="nofollow" class="ui sha label" href="{{.RepoLink}}/commit/{{.LastCommit.ID}}" rel="nofollow">{{ShortSha .LastCommit.ID.String}}</a>
+        <span class="grey">{{RenderCommitMessage .LastCommit.Summary .RepoLink}}</span>
       </th>
       <th class="nine wide">
-        <a rel="nofollow" class="ui green sha label" href="{{.RepoLink}}/commit/{{.LastCommit.ID}}" rel="nofollow">{{ShortSha .LastCommit.ID.String}}</a>
-        <span class="grey">{{RenderCommitMessage .LastCommit.Summary .RepoLink}}</span>
       </th>
       <th class="three wide text grey right age">{{TimeSince .LastCommit.Author.When $.Lang}}</th>
     </tr>