Adds restrictions for predefined work item types.

Changelog: added

Remove importers and specs

Changelog: removed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/121997

Moves definitions of mapping widgets for each work item type into DB.

Changelog: added

Merge branch 'update-security-with-canonical-changes' into 'master'

See merge request gitlab-org/security/gitlab!2942

Changelog: security

Adds restrictions for predefined types.

Changelog: added

Changelog: fixed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/95953
EE: true

Fixtures are needed for new installs. A migration was also added
for existing installs.

Changelog: changed

The plan for RSpec 4.0 is to disable monkey patching:
https://rspec.info/blog/2013/07/the-plan-for-rspec-3/#zero-monkey-patching-mode

This commit stops using RSpec monkey patching:
https://relishapp.com/rspec/rspec-core/docs/configuration/zero-monkey-patching-mode