Add support for OIDC RP-Initiated (Front-Channel) Logout Spec

[rcbjBlueMars]

This ticket will add a screen that allows the user to logout or end a session (ie, invalidate tokens associated with the session that the debugger has previously created).

It would be interesting to also be able to logout of sessions that were created outside of the browser, but doing this without it being confusing to the user or the logic for the rest of the debugger may be challenging.

See [1] for more information about Relaying Party initiated Logout with OIDC. The spec is only a few pages long and the call that needs to be made to the IdP is straightforward.

Populate as many of the parameters as possible from the OIDC Discovery Endpoint metadata and values collected from the user during the login process.

Reference: [1] https://openid.net/specs/openid-connect-rpinitiated-1_0.html [2] https://openid.net/specs/openid-connect-frontchannel-1_0.html