[DOC][ENHANCEMENT] Use the schema also in vscode

[BastianBalthasarBux]

To use the schema also in vscode, I would suggest to install the extension YAML by Redhat (redhat.vscode-yaml).
It comes already with a full bunch of schemas for YAML (e.g. Kubernetes).
Now you could add your own schemas.

• Go to: File -> Preferences -> Settings
• Search for "yaml: schemas"
• select "Edit in settings.json"
• Add this code:

  "yaml.schemas": {
        "https://raw.githubusercontent.com/georgringer/site-config-validation/master/siteconfig.json" : ["*/Configuration/Yaml/*.yaml"],
    },

(in fact, yaml.schemas is already written, you just have to add the second line for schema-file.)

Done.