Add incident hooks col to integrations

What does this MR do and why?

In #367550 (closed) we intend to add a new attribute for project integration settings.

This MR adds the base work that includes DB changes to add a new column in the integrations table.

Migrations

UP

main: == 20221228063845 AddIncidentEventsToIntegrations: migrating ==================
main: -- add_column(:integrations, :incident_events, :boolean, {:default=>false, :null=>false})
main:    -> 0.0268s
main: == 20221228063845 AddIncidentEventsToIntegrations: migrated (0.0386s) =========

Down

main: == 20221228063845 AddIncidentEventsToIntegrations: reverting ==================
main: -- remove_column(:integrations, :incident_events, :boolean, {:default=>false, :null=>false})
main:    -> 0.0031s
main: == 20221228063845 AddIncidentEventsToIntegrations: reverted (0.0144s) =========

How to set up and validate locally

1. Run the migration
2. Check the col in DB via rails console

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #367550 (closed)