Replace diverse uses of JSON Schema `$id` handling with utility functions

[julrich]

Stuff like this:

const componentPath = rootSchema.$id.split('/');
const componentType = path.basename(rootSchema.$id).split('.')[0];

return n.$id.replace(/#.*$/g, '');

export function getSchemaName(schemaId: string | undefined): string {
  return (schemaId && schemaId.split('/').pop()?.split('.').shift()) || '';
}

export function getSchemaModule(schemaId: string | undefined): string {
  return (schemaId && schemaId.split('/')[3]) || '';
}

Should all be handled by common JSON Schema $id helpers (like the last two).