Add project save functionality

[vkbo]

Summary:

This PR adds the basic functionality to save project data to JSON files. This includes copying over the static data class structure from the old Collett repository.

Related Issue(s):

Closes #6

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• Function descriptions are complete and understandable
• Only files that have been actively changed are committed