Is your feature request related to a problem? Please describe.
I love the vault tracking on alts SI does, with Delves now being a major part of weekly progress it would good to be able to see at a glance how many delves each character had completed and what tier they were.

Describe the solution you'd like
Exactly as it is for M+ and Raid now so if one character had done 4 Delves and 3 of them were 8 and one was a 2 it would display 8 | 2 to indicate vault

Describe alternatives you've considered
Zero alternative

Additional context
Delves vault progress shares with the open world so I assume there would be an impact there

Added in c964a22

I have introduced a few people to SI recently and one of the first thing commented on is how great it is but it's missing Delves :)

I didn't check the M+ code, but maybe it can be used as inspiration...

I checked the API to add related information, but it is difficult to trace the history.
It seems possible to show World reward information as N|N|N, just like M+ reward information is shown in N|N|N format.

It is currently being tested, and I will contribute when it is completed.

local worldActivities = C_WeeklyRewards.GetActivities(6)
for i, act in ipairs(worldActivities) do
  print(act.level)
end