I think the answer is 'yes" - it doesn't really make sense to use
gitlab for git hosting unless we also use it for bugs/issues.
If for no other reason than people will do so regardless ...
(Though I have mixed feelings about the "pull/merge request" way of working
- and we will always accept old-fashioned patches, we should also
accept merge requests on gitlab which suggests also using their issue tracker.)
Likewise feel free to host merge requests (pull requests) there.
If the experience is satisfactory I will update the manual
with the above link as where people should report and browse bugs.
I have no plans to migrate the old bugs from Savannah - I don't
know any practical way to do that.
There is nothing very wrong with Savannah's bug tracker,
and in some ways it is more elegantly minimalist and efficient.
However, I think most people would prefer gitlab's.