Remove the restriction that the Authority Rule must be configured

[RaigorJiang]

Hi community,

Since we have DistSQL, users can use Proxy without configuring any database.

However, when a user wants to experience Proxy, he must configure AUTHORITY rule in server.yaml, so that it can start successfully.
In fact, ShardingSphere provides DefaultAuthorityRuleConfigurationBuilder and DefaultUser, which can build a root user in the absence of Authority Rule Configuration. If we enable this feature, the user's first experience can be simplified to the greatest extent, because he can start it directly after decompression.

Currently, the reason why this feature cannot be enabled is that the authorityRuleConfig is checked in the ProxyConfigurationLoader and an exception will be thrown if it is empty.

YamlRuleConfiguration authorityRuleConfig = result.getRules().stream().filter(each -> each instanceof YamlAuthorityRuleConfiguration).findAny().orElse(null);
Preconditions.checkState(containsGovernance || null != authorityRuleConfig, "Authority configuration is invalid.");

I recommend removing this restriction and building a default root user for users when there is no Authority Rule Configuration.

[github-actions]

Hello , this issue has not received a reply for several days.
This issue is supposed to be closed.