Automate draft release / historical database upload

[khaeru]

Use actions/upload-release-asset and possibly actions/create-release to:

• Automatically create a GitHub release in draft state on a new tag like v*.
• Attach the (compressed) CSV version of the historical database as an asset associated with the release.

This will streamline the process of creating new Zenodo records that contain the latest database: after the above steps are done automatically, the release can be checked and taken out of draft state via the web interface. Then Zenodo will archive the repository, which should include the CSV asset.