(refs #1702)Implement keyboard shortcut "y"

which transfers a browser to URL with commit id.

src/main/twirl/gitbucket/core/repo/blob.scala.html

@@ -11,6 +11,7 @@
   @gitbucket.core.html.menu("files", repository){
     <div class="head">
       <div class="pull-right hide-if-blame"><div class="btn-group">
+        <a href="@helpers.url(repository)/blob/@latestCommit.id/@pathList.mkString("/")" data-hotkey="y" style="display: none;">Transfer to URL with SHA</a>
         <a href="@helpers.url(repository)/find/@helpers.encodeRefName(branch)" class="btn btn-sm btn-default" data-hotkey="t">Find file</a>
       </div></div>
       <div class="line-age-legend">

src/main/twirl/gitbucket/core/repo/files.scala.html

@@ -32,6 +32,7 @@
     <div class="head" style="height: 24px;">
       <div class="pull-right">
         <div class="btn-group">
+          <a href="@helpers.url(repository)/tree/@latestCommit.id/@pathList.mkString("/")" data-hotkey="y" style="display: none;">Transfer to URL with SHA</a>
           <a href="@helpers.url(repository)/find/@helpers.encodeRefName(branch)" class="btn btn-sm btn-default" data-hotkey="t"><i class="octicon octicon-search"></i></a>
           <a href="@helpers.url(repository)/commits/@helpers.encodeRefName(branch)/@pathList.mkString("/")" class="btn btn-sm btn-default"><i class="octicon octicon-history"></i> @if(commitCount > 10000){10000+} else {@commitCount} @helpers.plural(commitCount, "commit")</a>
         </div>