Similar to Jaybird's https://github.com/FirebirdSQL/jaybird/issues/746, add the SPDX information and add REUSE lint. See also [jdp-2025-01: Apply SPDX license info and comply with REUSE specification](https://github.com/FirebirdSQL/jaybird/blob/master/devdoc/jdp/jdp-2025-01-apply-spdx-license-info-and-comply-with-reuse-specification.adoc).