Clean up logout procedure

In my hurry to fix #172 (closed), I left the logout code in suboptimal state. I'd like to

• Check what the hydra-returned post-logout URL is necessary for, and if needed find some way to use it.
• See if we can now remove the logout endpoint from the dashboard, because we already do the kratos logout in prelogout.
• If so, change the default post-logout url to something else, possibly having a message saying you're successfully logged out.
• Also end the dashboard session on logout. I think we did that but it doesn't work right now at least.
• General clean-up of the relevant dashboard code.

added App::Dashboard label

If we upgrade to kratos 1.0, we can try to use its new return_to parameter for the hydra post-logout, so we no longer have to skip that.

changed milestone to %2.10

assigned to @arie

created branch 173-clean-up-logout-procedure to address this issue

mentioned in merge request !155 (merged)

added Doing label

marked the checklist item Check what the hydra-returned post-logout URL is necessary for, and if needed find some way to use it. as completed

marked the checklist item See if we can now remove the logout endpoint from the dashboard, because we already do the kratos logout in prelogout. as completed

marked the checklist item If so, change the default post-logout url to something else, possibly having a message saying you're successfully logged out. as completed

changed the description

marked the checklist item Also end the dashboard session on logout. I think we did that but it doesn't work right now at least. as completed

marked the checklist item General clean-up of the relevant dashboard code. as completed

added QA label and removed Doing label

closed with commit 289b3bea

mentioned in commit 289b3bea