Switch to running the Postgres init script manually during setup

This should hopefully fix the issue where some people run the setup script but no Postgres databases get created.

scripts/internal/firstrun-postgres-container.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+# shellcheck source=./framework.sh
+source "$(dirname "$(realpath "$0")")/framework.sh"
+parse_arguments "$@"
+
+print_info "Setting up the Postgres container..."
+
+load_dotenv postgres.env postgres.local.env
+postgres_init_script=$(cat "$git_base_dir/scripts/run-in-container/postgres-init.sh")
+
+compose_no_progress up -d postgres
+run_command_until_success "Waiting for Postgres to be ready..." 5 \
+    docker compose exec postgres psql -U "$POSTGRES_USER" -c "\\l"
+
+run_verbose docker compose exec postgres sh -c "$postgres_init_script"
+
+print_success "Postgres container is set up."