CI: Create a new route database periodically

[aardjon]

A new CI workflow shall automatically run periodically and:

• Retrieve the latest scraper release (i.e. the binary attached to the latest release tag)
• Execute the scraper to create a route database
• Push the created route database to a public space

This workflow can run on Github or somewhere else, but on an Ubuntu linux machine. It'd be perfect to publish the created route DB directly to our FTP (which cannot be accessed from Github runners), but another place like e.g. artifact storage is fine, too.

[aardjon]

As a starting point, the workflow is automatically triggered once per week on Github. The created artifacts (that is, route databases and log file) are stored as artifact and can be downloaded from there.

It's also possible to trigger the workflow manually, of course.