Add more details to quantify contribution for each member

**Is your feature request related to a problem? Please describe.**
We can only know the total number of PRs and issues created by the member but no specific details.

**Describe the solution you'd like**
Split the total count into "issues created", "number of PR made" and ("number of PR reviewed" vs "number of PR review comments") and display multiple numbers beside the user profile photo. The meaning of the number will be displayed when we have the mouse hovering over the number.

**Describe alternatives you've considered**
While also having splitter count, we may have icons to indicate the meaning of the number. -- But I am unsure about what the icons should look like.

**Additional context**
I think number of PR reviewed and number of PR comments made are good but similar metrics to measure a member's contribution on reviewing PR and keeping one of them should be sufficient. However, I am unsure about the best way to present the data.

Start by tracing the member profile view and the existing data used for total PR and issue counts. Review how contribution information is currently displayed beside the profile photo. Done means the selected contribution metrics are shown separately, with their meanings available on hover; the issue leaves the exact metric and visual treatment open for design discussion.

Written by the indexing model from the issue text.