Adjust OpenId server settings deploy source to match recipe step, #6364

[kaipm]

Refactor OpenIdServerDeploymentSource to be readable by the current implementation of OpenIdServerSettingsStep.

The server settings deployment source output is changed from:

...
"steps": [
  {
    "name": "OpenIdServer",
    "OpenIdServer": {
        ...
    }
  }
]

to:

...
"steps": [
  {
    "name": "OpenIdServerSettings",
    ...
  }
]

Partially deals with existing issue, see #6364

[kaipm]

It seems the C# 9.0 new() shorthand is the issue, in the new file MemoryFileBuilder...

I'm sorry, already on it to push a fix.