Every now and then people ask about plugins for Kolla. This conversation
may need to be revisted in more detail soon, but till then it's worth
highlighting what we do currently support in Kolla.
Right now adding the block as shown in this patch will make the plugin
archive available in the image, but currently only Neutron has
Dockerfile directives to automatically install them if present. The same
can be added very easily for other commonly pluggable services such as
Horizon.
Change-Id: Ia52d5ccf753667c5452b19fcaf4bf5b893a59fd0
8b3d3ef84e
