Gets rid of unnecessary copying and makes things more explicit by using
a struct with named fields instead of a tuple for tie breaking.
Co-authored-by: Jonathan de Jong <jonathan@automatia.nl>
In a previous commit I moved the auth chain calculation code to ruma
because I thought I could optimize it by only taking auth chains from
conflicted events instead of all events. It turned out that was wrong
and now I removed that algorithm again (the full auth chains are now
passed in as an argument to state_res::resolve again).
