Consictency issue in the server setup index for the dotnet version requirements.

[wvangulik]

In the

• https://github.com/spacebarchat/docs/blob/master/docs/setup/server/index.md

and

• https://github.com/spacebarchat/docs/blob/master/docs/setup/server/adminApi/index.md
  files, it's referenced that dotnet 9.0+ is needed. However the

• https://github.com/spacebarchat/server/blob/master/extra/admin-api/Spacebar.AdminApi/Spacebar.AdminApi.csproj
  file forces Dotnet 10, this prevents the build of the application.