Adds a project member to the project with the specified id.
Adds a project member to the project with the specified id.
The new project member can also be set as a responsible project member, but only if no other member of this project is responsible.
It is necessary that the project role is available in this project, otherwise the member cannot be added.
A project role is available when they are connected to the specified project type of the project.
A user can only be added to the project once.
<Check title="Required Permissions" icon="key">The user has to be the creator or needs `project-master-data:manage` permissions on the project.</Check>

