New personal access token API endpoint 'id'

Proposal

To view the properties of a personal access token (PAT) via the API, the user currently needs to retrieve a list of all his PATs. He can do this by submitting a valid PAT via the API call. The admin can additionally display the PATs of a specific user using the user_id parameter, but a complete list of all PAT properties always comes with it. In order to not always have to query the complete list, it would be possible to query only a specific PAT by providing a parameter that gets the PAT by its id. The API call looks like this:

[GET api/v4/personal_access_tokens/id]

Command:

curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/personal_access_tokens/3"

Trying to access a PAT that does not exist should return a 404 error not found and an unauthorized one should return the 401.

Implementation Plan

• Add a new route to lib/api/personal_access_token.rb which receives a parameter :id