Adding keycloak-client guides

[rmartinc]

Adding the guides for keycloak-client. Main changes:

• It needs to download the new keycloak-client-guides dependency to also obtain guides from that project.
• Images should also be retrieved from the new dependency.
• I'm setting the version of the client as a system property. We can do something fancier but I think this is OK (it's just to know the version of client used, nothing more).

This cannot be merged until we have a real keycloak-client release (if you see I'm using the snapshot version). So tests are gonna fail for sure. Maybe we can change the add-version.sh to receive the keycloak version and the keycloak-client version (or guess it from the dependency? Don't know if possible). Draft because it cannot be merged yet.

Check the PR in keycloak-client for images.

Related PRs:

• PR for keycloak-client: Move documentation to keycloak-client keycloak-client#28
• PR for keycloak: Move documentation to keycloak-client keycloak#32187

@stianst @mposolda Take a look when you have time. It's just a first idea. The sample images are in the keycloak-client PR.

[mposolda]

@rmartinc Thanks!

[stianst]

I think it may be great to be able to support multiple categories within keycloak-client, and allow mixing in guides from server repo and client repo into the same category.

For example keycloak-client could use more than one category, put some guides into getting-started some into securing apps.

[stianst]

Version stuff works for now, but we'll most likely also want client release blog posts, so would need a way to enumerate all the client library versions for that. That should be in a follow-up though.

[rmartinc]

@stianst Changes requested done. I have also removed the system property and I'm using now the ${properties["version.keycloak.client"]} to access the maven properties. This way we don't use any system property.

And yes, maybe we need to add versions for the client too. But we can do that when we need it.

[stianst]

Do not merge until Keycloak client libraries have been released, and version.keycloak.client is updated in the pom.xml.

[stianst]

Incorporated in #494 - we just need to enable the client guides after the artifact is available.