create a new login page

this page is used for the session timeout or first login.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Yu Xin Huo <huoyuxin@linux.vnet.ibm.com>
redirect the URL to login page when session timeout or first login

If the content type is application/json still raise 401 status code.
And let UI redirect to login page.

or the backe redirects to login page directly.

enable kimchi-ui.html authentication protected.
and update the test case

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Yu Xin Huo <huoyuxin@linux.vnet.ibm.com>
when login successfully, redirect to the last page.

let cookie remember the last page.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
Signed-off-by: Yu Xin Huo <huoyuxin@linux.vnet.ibm.com>
login page prompts error when username or password is wrong

when username or password is wrong, come back to login page with an error message.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
login page prompts error when session timeout

When session timeout, come back to login page with an
error message.

When session logout, close session directly.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
login: update test config case

change some config of cherrypy root. update the test case.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>