Council and election pages: Small enhancements

[Lezek123]

There are a few low-cost enhancements that could be executed relatively quickly to improve Council/Elections data visibility.
Most of those issues were already reported / mentioned a long time ago. I linked them below, so they can be closed afterwards.

Council page

1. Add term start and end (estimated) dates for current term
   • [USERSNAP] Council: Doesn't display specific date/time/block that the council started at #3124
   • Council time remaining #1283
2. Add current term number
   • [USERSNAP] Wrong council number representation #3179

Past council page

1. Display term number instead of id in the header
   • [USERSNAP] Wrong council number representation #3179

Past councils listing

1. Display term number instead of id in the TERM column
   • [USERSNAP] Wrong council number representation #3179

Current elections

1. Add voting statistics:
   • total number of votes & total voting stake during Voting and Revealing period
   • total number of revealed votes & total revealed votes stake during Revealing period
   • related issue: Elections: Election statistics #4707

Past election page

1. Add election result (+ elected council link if elected)
   • Problem: Lack of clarity regarding failed elections #3426
2. Highlight elected council members
   • Show elected/ not elected distinction in past councils #3189
3. Add Revealed votes stake / Total votes stake statistic
   • Elections: Election statistics #4707'

Past elections listing

1. Add election result (successful / failed)