add `use_for_new_networks` column in controller table

ext/central-controller-docker/migrations/0004_use_controller_flag.down.sql

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+ALTER TABLE controllers_ctl DROP COLUMN IF EXISTS use_for_new_networks;

ext/central-controller-docker/migrations/0004_use_controller_flag.up.sql

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+ALTER TABLE controllers_ctl ADD COLUMN IF NOT EXISTS use_for_new_networks boolean DEFAULT true NOT NULL;