[feature] the basic framework of capstan TODOs

[mozhuli]

Testing workload：

• [P0] Basic workflow of capstan Add basic framework #3 @mozhuli
• [P0] The interface of workload Add basic framework #3 Enhance workload and testing tool interface #6 @mozhuli
• [P0] The interface of testing tool Add basic framework #3 Enhance workload and testing tool interface #6 @mozhuli

Collect data:

• [P1] Basic workflow of data collecting Export testing results to prometheus #11 @mozhuli
• [P1] The interface of data collecting Export testing results to prometheus #11 @mozhuli

Dashboard(grafana):

• [P1] Design a generic template of dashboard

/cc @ZJU-SEL/capstan-dev