Dashboard Spring Boot Configuration more flexible support

## Issue Description

Type: *feature request*

### Describe what happened (or what feature you want)

Make dashboard more extensible.

### Describe what you expected to happen

Spring Boot Configuration more flexible

Use `@ConditionalOnMissingBean` not `@Component` directly, combine with `@Configuration` to create a bean.

For example, about `MachineDiscovery`.

We can write code like follow

```java
@Configuration
public class MachineDiscoveryConfiguration {

@Bean
@ConditionalOnMissingBean
public SimpleMachineDiscovery simpleMachineDiscovery() {
return new SimpleMachineDiscovery();
}

@Bean
@ConditionalOnMissingBean
public AppManagement appManagement(SimpleMachineDiscovery simpleMachineDiscovery) {
return new AppManagement(simpleMachineDiscovery);
}

}
```

And delete annotation `@Component` above class `SimpleMachineDiscovery` and `AppManagement`.

If someone want to custom their `AppManagement`, that will make it more easy.

Same principle can apply to `RuleRepository`, DynamicRuleProvider, DynamicRulePublisher too.

Locate SimpleMachineDiscovery, AppManagement, RuleRepository, DynamicRuleProvider, and DynamicRulePublisher, then inspect how their Spring beans are currently declared. Compare that setup with the proposed @Configuration and @ConditionalOnMissingBean approach, and verify that applications can provide custom beans without conflicts.

Written by the indexing model from the issue text.