By the look of it, it seems close to what section "Initiating Login from a Third Party" of [OIDC core spec](https://openid.net/specs/openid-connect-core-1_0.html#ThirdPartyInitiatedLogin) describes. And what is known as "IDP-initiated SSO" in SAML world.
Usage of both isn't considered a good practice, yet some vendors decide to go in this direction anyway. Gluu Server already allows user to be authenticated just once, and then be able to access the rest of their services without providing credentials again. They just need to access the site they need first, using the usual navigation practices (like browser bookmarks).
Gluu Server supports both the OIDC and SAML way of initiating authentication flow from OP/IDP, but there is no web UI like the one described in the article you referenced. To start a flow like this, an uri of specific format needs to be manually crafted.
So, in a nutshell, there is nothing like that, but if it's really needed, you could develop an auxiliary web app that would display all services supported by your organization, and upon user clicking on an icon would just redirect them to a certain uri pointing to your Gluu Server where authentication will happen, if needed. In such simple form the list of apps won't be personalized. If this is also a requirement, then auxiliary web app could first authenticate the user itself, then use SCIM to fetch a list of apps they have registered from Gluu Server - and then allow them to select one.
Hope this helps.