Adding a "Default relations" section to all types of projects

[vizthex123]

CurseForge has this on a couple of project categories, and it's quite nice.

It's really annoying to have to constantly re-enter the same things every time i upload new versions of my datapacks, so being able to have defaults added to all newly uploaded versions (that you can easily remove or change the status of if needed) would be lovely.

Also, there needs to be a link to this on the website. I couldn't find one anywhere, and only got here because i finally caved and joined the discord server after a user there gave me a link to this.