As discussed in the horizon meetings or in horizon PTG sessions,
horizon team agreed to deprecate django version of Images, Keypair
and Roles panel as we think that feature gaps between the two
implementations have been closed. Let's mark the Django version as
deprecated for all these panels and gather more attention
from operators.
Change-Id: I965f9dbdd5e78b52a788f73b359c1c6fbc18637e