invert package dependency between identity<-->entity

api/graphql/models/lazy_bug.go

api/graphql/resolvers/mutation.go

bridge/github/export.go

bridge/github/export_test.go

bridge/github/import_integration_test.go

bridge/github/import_test.go

bridge/gitlab/export.go

bridge/gitlab/export_test.go

bridge/gitlab/import.go

bridge/gitlab/import_test.go

bridge/jira/export.go

bridge/jira/import.go

cache/bug_cache.go

cache/bug_excerpt.go

cache/bug_subcache.go

cache/cached.go

cache/identity_cache.go

cache/identity_subcache.go

cache/repo_cache.go

cache/subcache.go