inconsistent order of JSON nodes in .egn file makes diffing versions harder

[hofstef]

Describe the bug
When a domain story is exported multiple times, the sequence of the JSON nodes in the .egn file is different every time. This has no effect on the functionality of Egon (ie, importing still works fine and semantically, the stories are the same). But users who put their .egn files in a sourcecode repository like Git will have a hard time to see actual changes in their files.

This seems to happen only in Firefox, not Chrome.

To Reproduce
[If applicable, attach a .dst file. ]
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Click on '....'
4. See error

Expected behavior

• Only JSON nodes that have actually changed should be different from the previous .egn file.
• Exporting the same Domain Story twice should result in the exact same .egn file.

Version

• Egon: v2.1.0
• Browser: Firefox
• OS: Windows