Spec Lite: 'all' visibility image filter

project: glance
problem: When deployments use community images these community images are not returned when doing an image list. Currently murano and other projects use a property to determine if the image should be used. It is not possible to filter on all images with the specific property. Sahara also shares this issue. Horizon currently also needs to show all images that a user can boot from in the boot intance view and this cannot be done without 2 requests to glance.
solution: We need to add a new visibility called 'all' which will return all images that are available to the user.
impacts: None
how: We will add the ability to list images with visibility='all' to return all images. This will require a bump in the api version.
alternatives: The other option is to make 2 requests to glance each time you want to list all images or filter by all images which is inefficiant
assignee: sorrison