proposal: add the security-triage team as security manager of the organizations

Now that it's possible to submit reports through GitHub, it would be good to add the security triage team so they can handle them, which would reduce the tasks of the TC.

We should also find a way for the captains to have access to these reports, although with this change, it would no longer be necessary for a TC to be involved in the delivery process, since a triage member could coordinate with the captains and handle the release.

This would also mean that we need to replicate the security triage team in the other organizations we have.

This can be done by assigning a role to a person or a team (https://github.com/organizations/expressjs/settings/org_role_assignments)