Share API responses types/interfaces with the frontend

[ZibanPirate]

Description

after deploying #289 to stage, the frontend crashes, that was due to the changes in api response of /v2/Contributors. To prevent such problems in the future, we need to share the API response type/interface with the frontend.

Check List

1. Move all new endpoint response types/interfaces (here and here) from api folder to common folder inside common/src/types/api-responses.ts
2. use these types on the frontend here and here

Additional Comments

this task is blocked by #290 , once it's merged, will add a third task to share the response interface of the new GithubUser controller too, then we can start working on this one

[ZibanPirate]

i will take up this task, once #290 is merged