Logout POST action (#10582)

* Change logout to POST

* Update for redirect

Signed-off-by: jolheiser <john.olheiser@gmail.com>

templates/base/head_navbar.tmpl

@@ -115,7 +115,7 @@
 					{{end}}
 
 					<div class="divider"></div>
-					<a class="item" href="{{AppSubUrl}}/user/logout">
+					<a class="item link-action" href data-url="{{AppSubUrl}}/user/logout" data-redirect="{{AppSubUrl}}/">
 						{{svg "octicon-sign-out" 16}}
 						{{.i18n.Tr "sign_out"}}<!-- Sign Out -->
 					</a>