Call `zk` from other programs

Calling zk from other programs can be useful in a number of situations, such as:

creating notes from your text editor using a custom shortcut
creating a reference note from the text selected in your web browser
automating periodical maintenance tasks on your notebook
displaying the backlinks of a note in a GUI wrapper around zk

The following options can be useful to make sure zk behaves properly in a background context:

--no-input disables all user prompts and ignores --interactive
--quiet reduces unnecessary output