/// Retrieves the <see cref="IRulesetConfigManager"/> for a <see cref="Ruleset"/>.
/// </summary>
/// <param name="ruleset">The <see cref="Ruleset"/> to retrieve the <see cref="IRulesetConfigManager"/> for.</param>
/// <returns>The <see cref="IRulesetConfigManager"/> defined by <paramref name="ruleset"/>, null if <paramref name="ruleset"/> doesn't define one.</returns>
/// <exception cref="InvalidOperationException">If <paramref name="ruleset"/> doesn't have a valid <see cref="RulesetInfo.ID"/>.</exception>