Versioning for template.json schema

Consider establishing the versioning schema for `template.json` schemas:
- all previous version to use current schema - `template`
- n+1 version: template.json should be versioned as `template-`, example: `template-9.0.200`
- in case there is no changes to schema in certain version, the version is skipped.

Subtasks:
- [ ] release new version of `template-` schema to schemastore.org
- [ ] document schema versioning
- [ ] Implement check for schema version when running the template (based on $schema) - in case template version is higher than dotnet version, raise a warning (can be done via validation https://github.com/dotnet/templating/issues/2623)