Reduce the number of connection requests

[Mini256]

Description

On the current website, each metric number needs to initiate a database query. When the user browses a page, it may send 10~20 query requests to the database.

Tasks

• [ ] 1. Combine some small query (#678, #685)

For example, the above screenshot needs to send 4 requests (/q/pull-requests-total、/q/pull-request-creators-total、/q/pull-request-reviews-total、/q/pull-request-reviewers-total), we can combine these queries into one, like /q/pull-request-summary.

• [ ] 2. Use WebSocket to push events-total-increment

The current web page needs to obtain real-time event data through the poll, WebSocket will be a better way to achieve it.