update ranking of prvs, only load once

[tomholub]

I guess, needSigning and expiration should be considered here too,
so rank function would be too complicated.
We'd be better off with a sorting lambda like

.sort( (a, b) => {
  if (needSigning && a.senderKis.length && !b.senderKis.length) {
    return -1;
  }
  if (needSigning && !a.senderKis.length && b.senderKis.length) {
    return 1;
  }
  ... other conditions
}

Originally posted by @rrrooommmaaa in #4372 (comment)

[tomholub]

[tomholub]