Only restart components that modify configuration

[kissmydb]

from：戚铮、李坤
现象：没有修改配置，reload 不指定 role 或 node 时会，也重启整个集群
建议：自动识别修改了哪个组件的配置，如果没有修改就跳过

[lucklove]

It seems we will get into trouble if the user modify ports.
For example, if one modifies the pd port, other services connected to pd should be re-config and reload too.

[lonng]

@lucklove Some fields are limited to modify and I think we can implement this feature base on changing fields.
cc @AstroProfundis