[Feature] Add data-source extension for OpenSergo rate limiting and fault-tolerance spec

[sczyh30]

Issue Description

Type: feature request

Describe what feature you want

OpenSergo is a universal microservice governance specification, which covers fundamental scenarios like traffic routing, rate limiting and fault-tolerance.

Sentinel 2.0 will be the standard implementation of OpenSergo traffic governance spec (including traffic routing, rate limiting and fault-tolerance). Since Sentinel Go has already provided capabilities of rate limiting and microservice fault-tolerance, we could just add a data-source extension, which subscribes rules from the OpenSergo Control Plane, convert the rules to Sentinel rules, then developers could register the data-source to rule managers of Sentinel.

Additional context

• OpenSergo fault-tolerance v1alpha1 spec: https://github.com/opensergo/opensergo-specification/blob/main/specification/zh-Hans/fault-tolerance.md
• Structure of OpenSergo operator and SDK: Structure of OpenSergo operator and SDK opensergo/opensergo-specification#17
• OpenSergo Go SDK: https://github.com/opensergo/opensergo-go-sdk

Related issue of Sentinel (Java): alibaba/Sentinel#2841