Add author_id column to vulnerability_state_transitions table

What does this MR do and why?

This merge request adds a new column (author_id from users table) to the vulnerability_state_transitions table. It also adds a foreign key constraint to the table as requested in #367859 (closed)

For database review

main: == 20220723120039 AddAuthorIdToVulnerabilityStateTransitions: migrating =======
main: -- add_column(:vulnerability_state_transitions, :author_id, :bigint)
main:    -> 0.0061s
main: == 20220723120039 AddAuthorIdToVulnerabilityStateTransitions: migrated (0.0066s) 

main: == 20220726182310 AddUserFkToVulnerabilityStateTransitions: migrating =========
main: -- transaction_open?()
main:    -> 0.0000s
main: -- index_exists?(:vulnerability_state_transitions, :author_id, {:name=>"index_vulnerability_state_transitions_on_author_id", :algorithm=>:concurrently})
main:    -> 0.0084s
main: -- execute("SET statement_timeout TO 0")
main:    -> 0.0003s
main: -- add_index(:vulnerability_state_transitions, :author_id, {:name=>"index_vulnerability_state_transitions_on_author_id", :algorithm=>:concurrently})
main:    -> 0.0046s
main: -- execute("RESET statement_timeout")
main:    -> 0.0008s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- foreign_keys(:vulnerability_state_transitions)
main:    -> 0.0068s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE vulnerability_state_transitions\nADD CONSTRAINT fk_e719dc63df\nFOREIGN KEY (author_id)\nREFERENCES users (id)\nON DELETE CASCADE\nNOT VALID;\n")
main:    -> 0.0045s
main: -- execute("ALTER TABLE vulnerability_state_transitions VALIDATE CONSTRAINT fk_e719dc63df;")
main:    -> 0.0076s
main: == 20220726182310 AddUserFkToVulnerabilityStateTransitions: migrated (0.0543s)

main: == 20220726182310 AddUserFkToVulnerabilityStateTransitions: reverting =========
main: -- transaction_open?()
main:    -> 0.0000s
main: -- remove_foreign_key(:vulnerability_state_transitions, {:column=>:author_id})
main:    -> 0.0100s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- indexes(:vulnerability_state_transitions)
main:    -> 0.0054s
main: -- execute("SET statement_timeout TO 0")
main:    -> 0.0004s
main: -- remove_index(:vulnerability_state_transitions, {:algorithm=>:concurrently, :name=>"index_vulnerability_state_transitions_on_author_id"})
main:    -> 0.0118s
main: -- execute("RESET statement_timeout")
main:    -> 0.0009s
main: == 20220726182310 AddUserFkToVulnerabilityStateTransitions: reverted (0.0485s) 

main: == 20220723120039 AddAuthorIdToVulnerabilityStateTransitions: reverting =======
main: -- remove_column(:vulnerability_state_transitions, :author_id, :bigint)
main:    -> 0.0012s
main: == 20220723120039 AddAuthorIdToVulnerabilityStateTransitions: reverted (0.0025s) 

Related to #367859 (closed)