Update Kiota client to Keycloak 26.5.2 including other dependencies

[roycornelissen]

🧑‍💻 chore: update Keycloak to 26.5.2

Update Keycloak version from 26.4.2 to 26.5.2 in docker-compose files and documentation.

chore: update Kiota client to api 26.5.2

• Update Kiota client to api 26.5.2
• Update Kiota tool to 1.30.0
• Update Microsoft.Kiota.Bundle to 1.21.3
• Fix csproj VersionPrefix
• Clean generated folders before generating client

chore: remove intermediate Kiota generated client code

Removed the Admin and Models folders from the repository root, they are probably intermediate results

chore: update Nuget dependencies

Fixes #190

[NikiforovAll]

@roycornelissen could you please explain the number of deletions we see in this PR?

[roycornelissen]

@NikiforovAll that was actually an assumption I made, I noticed that there were Admin and Models folders in the root of the repo as well as in the src/Keycloak.AuthServices.Sdk.Kiota project folder. I think the ones in the root originated from someone running the Kiota generator from the root of the repo at some point, but they seemed redundant to me, as they are not compiled or used in the project.

I did this in a separate commit so if this unwanted, I can take out the commit.