feat: Export renku project to zenodo/dataverse
Allow exporting of a snapshot of a renku project to zenodo/dataverse to get a DOI. Code and Data should be exported (but without the whole git history)
This was discussed in a design meeting (meeting's notes: https://sdsc.atlassian.net/wiki/spaces/RENKU/pages/2139521025/2021-11-11+Design+meeting+notes) and we decided to have an initial implementation which would export the project as a tarball (implementation details need to be discussed). We need to export the whole history to have a fully-functional renku project.
Related: https://github.com/SwissDataScienceCenter/renku-python/issues/1328 https://github.com/SwissDataScienceCenter/renku-python/issues/1327