Write a function that writes the eml.xml file (can copy over from collectory) #10
Description
Notes on licence:
- define licence as a constant class and have string user can put in the metadata.md file that will refer to the correct licence
- do we include a prompt in the terminal for the user in case guidance doesn't work? for example, if they try to make the eml.xml file but don't specify the right string for cc-by4.0, we can give them a list of accepted licences with numbers next to them, and the user enters the number for the license they want