Add possibility for release notes on a module version

[quintesse]

I think it would be very useful to have the possibility of explaining what exactly was changed in a new version that gets uploaded. If the module has a link to a GitHub project set we could perhaps automatically set it to point to the /releases link, but it would be nice if it was a free field where people could add whatever documentation they want.

[gavinking]

I like the idea.

[FroMage]

What, like https://herd.ceylon-lang.org/modules/ceylon.net/1.2.2/changelog? ;)

[quintesse]

Hah, didn't even know that was there!

[luolong]

@FroMage the link above asks for my credentials ...

[FroMage]

Because you don't have permission to edit it. But it still works ;)