horizon already deprecated launch instance Django based implementation
in the wallaby cycle [1]. This patch remove code for launch instance
Django based implementation as angular based implementation is the
default one from long and all features gaps between angular and Django
implementation is closed.
It also moves SetAdvanced step code to ``resize_instance.py`` as
``workflows/create_instance.py`` file is deleted and remove server_group
option from Advanced Options of resizing instance action because
"server_group" is not required while resizing an instance as per
nova-api reference [2].
Closes-Bug: #1869222
[1] https://review.opendev.org/c/openstack/horizon/+/779125
[2] https://docs.openstack.org/api-ref/compute/?expanded=resize-server-resize-action-detail#resize-server-resize-action
Change-Id: I5e01cd81f309491f1a58ea93911030366a86e3c7
6ac31e0ba8