Project-specific user permissions

### Current Behavior

Currently (in version 4.8.2) it is not possible to grant project-specific permissions to users.
It would be interesting to be able to restrict access to only a subset of existing projects for users/teams.
There may be confidentiality clauses between projects.

### Proposed Behavior

Add more permissions options to allow access only to certain projects.

### Checklist

- [X] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/CONTRIBUTING.md#filing-issues)
- [X] I have checked the [existing issues](https://github.com/DependencyTrack/dependency-track/issues) for whether this enhancement was already requested