static: Hides password error message on login screen when typing

When the user begins to change the text inside the "User name" or
"Password" input fields, the "Wrong password message will be hidden
until it is confirmed wrong again.

Reviewed-by: Stef Walter <stefw@redhat.com>
static: Disables log in button when logging in

When the user clicks the log in button, the button will be disabled
while the user name and password are being verified. While the fields
are being verified, the "Wrong username or password" dialog will be
hidden if already shown.

Reviewed-by: Stef Walter <stefw@redhat.com>
static: Added throbber to login page when logging in

as the user waits for the authentification to pass or fail there will
now be a throbber to indicate the page is still responding

Fixes #914
Closes #945
Signed-off-by: Stef Walter <stefw@redhat.com>
 * Install waiting.gif into the right place
 * Remove waiting.gif from shell module