Could you add a module like spring-cloud-alibaba-dependencies

## Issue Description

Type: *feature request*

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

能加一个类似于spring-cloud-alibaba-dependencies的bom模块吗

> Could you add a module like spring-cloud-alibaba-dependencies

### Describe what you expected to happen

Spring Cloud Alibaba引用的sentinel模块版本一般总是滞后的，但现在如果想要修改那个版本（比如1.8.0-》1.8.1），就需要把所有的sentinel模块都声明一遍，实在太多了，而且后续你们如果对模块进行增删改，我们的项目里就可能会报错。

> The sentinel module version referenced by Spring Cloud Alibaba is usually late, but if you want to change that version (e.g. 1.8.0- 1.8.1), you need to declare all sentinel modules. There are too many, and if you add, delete or change the modules later, We might get an error in our project.

通过bom模块可以将sentinel所有的内部模块都放在一起统一进行版本管理，我们只需要声明一个bom就行了。

> Through the BOM module, all sentinel internal modules can be put together for unified version management. We only need to declare a BOM

The request names a new BOM module like spring-cloud-alibaba-dependencies, covering Sentinel's internal modules. No files or tests are identified, so first locate the existing dependency-management modules and Sentinel module declarations. Done means consumers can manage the internal module versions through one BOM declaration and override the Sentinel version centrally.

Written by the indexing model from the issue text.