[10.3] Migrate `can_push` column from `keys` to `deploy_keys_project`
See merge request gitlab/gitlabhq!2276
(cherry picked from commit f6ca52d31bac350a23938e0aebf717c767b4710c)
1f2bd3c0 Backport to 10.3
In 8278b763d9 the default behaviour of annotation
has changes, which was causing a lot of noise in diffs. We decided in #17382
that it is better to get rid of the whole annotate gem, and instead let people
look at schema.rb for the columns in a table.
Fixes: #17382
