Currently, deltachat-repl has a command to add a contact by e-mail address, but as far as I can tell, it does not have a command to add a key contact. This would be a useful ability to have for various types of testing. The import_vcard() and make_vcard() operations defined in src/contact.rs provide the necessary functionality for importing and exporting key contact information. We just need to bind these functions to commands in the repl.

I plan to submit a pull request that implements this enhancement.