Add a clean logout with Keycloak

[rhoud]

Base information

Question	Answer
Related to a SourceForge thead / Another PR / Combodo ticket?
Type of change?	Enhancement

Symptom (bug) / Objective (enhancement)

When authentication to iTop is done with Keycloak, at the logout, the session at Keycloak's level is not released.

Proposed solution (bug and enhancement)

In specific case of login mode with "hybridauth-Keycloak", retrieve keycloak parameters from configuration's file and send a logout to end the keycloak session and update the url redirection attribut.

Checklist before requesting a review

• I have performed a self-review of my code
• I have tested all changes I made on an iTop instance (release 3.2.0) and with Keycloak release 25.0.0
• Would a unit test be relevant and have I added it? => Unable to run the unit tests from this repo alone.
• Is the PR clear and detailed enough so anyone can understand digging in the code?

[jf-cbd]

Hello @rhoud, thanks for your Pull Request !
Even if your solution would fix the problem, your implementation has some limits (it's not generic - only for Keycloak case ; there is no option to let the administrator choose if users should - or not - get disconnected from Keycloak).
On our side, we did a Pull Request (hybridauth/hybridauth#1420) from our fork of hybridauth to hybridauth repository to do the same thing, so it could be a generic way to disconnect from any IdP in combodo-hybridauth.
I'll keep you updated when we'll implement this feature :)