Show git providers in Admin user detail

[laushinka]

A lot of customer support involves looking up git providers for users.
It would help to show the list of git provider integrations that a user has, together with the userID and/or email for each.

[jldec]

Unscheduled.

Clarified that the list of integrations should also show the userID and/or email which is specific to each integration.

[jldec]

Scheduled because #8645 is in progress, and this is a common support need.