Login Module - Current URL is used in the action parameter of the form
Set the called URL as the action attribute value
Merge pull request #5346 from Kubik-Rubik/mod_login-form-action-url

Login Module - Uses current URL in the action attribute of the form element
 [imp] remove index.html form XML's Frontend module (Fixes: #5396)
[imp] remove index.html from XML of administrator/components/com_[n-z]
(fixes #5393 )
[imp] remove index.html from XML of administrator/components/com_[a-m]
(Fixes #5394 )