【Feature】make pev/pev2 pluginable

[akaError]

pev2 has successfully built upon pev, and I greatly appreciate your contribution! Please allow me to introduce myself first. I am a member of Oceanbase (under Alibaba/Alipay) . I found this interesting project because I am trying to improve the observability and usability of Oceanbase for non-expert users.

Previously, I had no experience in front-end development and only develop the SQL kernel of Oceanbase with cpp. In a short time, I have been struggling to figure out how to modify the pev2 project to be compatible with Oceanbase due to my lack of front-end development experience. On one hand, the project documentation is relatively sparse (English is not my first language, and I hope this request doesn't offend you), and on the other hand, I am considering whether it is possible to make this project pluggable to support different database backends.

As an SQL kernel optimizer professional, many good ideas in my mind to present specialized kernel knowledge with visual secondary development, such as the decision-making process of the optimizer. If I could have your help and guidance, it would save me a lot of effort.