Clone topics from GitHub when importing
### Problem to solve
GitHub has so-called topics.
GitLab has so-called tags (not in git sense).
But when importing a project from GitHub, tags are not populated from topics.
### Proposal
I guess they should.
### Documentation links
[GitHub topics](**url**)
[GitLab topics API](https://docs.gitlab.com/ee/api/topics.html#topics-api)
issue