Provide basic support to form management.

Support form_id in login_form from request as something "hidden", which can be
preprocessed as url and later passed to authentication backend.

master/bt5/vifib_web/SkinTemplateItem/portal_skins/vifib_hosting/WebSection_viewVifibKVMOrder/your_login_button.xml

@@ -232,7 +232,7 @@
 <tr><td align=center><br></td></tr>\n
 <tr><td align=center><img src="vifib.kvm?format=png&display=xsmall"></td></tr>\n
 <tr><td align=center><br></td></tr>\n
-<tr><td align=center><a class="nolabel validate alignr" href="./login_form">Login to Order your VM</a></td></tr>\n
+<tr><td align=center><a class="nolabel validate alignr" href="./login_form?form_id=WebSection_orderVifibKVM">Order your VM</a></td></tr>\n
 <tr><td align=center><br></td></tr>\n
 </table>\n
 </div>\n

master/bt5/vifib_web/SkinTemplateItem/portal_skins/vifib_jauks_theme/login_form.xml

@@ -57,6 +57,9 @@
           <tal:block tal:condition="python: request.get(\'came_from\', None) is not None">\n
             <h1 i18n:translate="" i18n:domain="ui">You do not have enough permissions to access this page.</h1>\n
           </tal:block>\n
+          <tal:block tal:condition="python: request.get(\'form_id\', None) is not None">\n
+            <tal:block tal:define="came_from python: request.set(\'came_from\', \'/\'.join([here.getWebSiteValue().absolute_url(), request.get(\'form_id\', None)]))"></tal:block>\n
+          </tal:block>\n
           <input tal:condition="exists: request/came_from"\n
                  type="hidden" name="came_from"\n
                  tal:attributes="value request/came_from" />\n

master/bt5/vifib_web/bt/revision

-397
\ No newline at end of file
+398
\ No newline at end of file