let repo admin select the user a status is send back

[6543]

see https://github.com/woodpecker-ci/woodpecker/issues/558#issuecomment-987456959

It could happen that the original user who activated a repo reject there oauth2 access or left the project, dont have the rights anymore ... Or you want to set it to a "bot" account ...

in all cases you at the moment have to change that in the database manually :/ - change that!