This patch adds support for MFA TOTP on openstack dashboard.
A new configuration variable OPENSTACK_KEYSTONE_MFA_TOTP_ENABLED
was added false by default.
If enabled, users needing TOTP are prompted with a new form.
keystone doc: https://docs.openstack.org/keystone/latest/admin/auth-totp.html
Demonstration video : https://youtu.be/prDJJdFoMpM
Change-Id: I1047102a379c8a900a5e6840096bb671da4fd2ff
Blueprint: #totp-support
Closes-Bug: #2030477