Add ability to see and sort on vote count from Issues and MR lists

Fixes #3763

* Sort options

![Sort Options](/uploads/df6543d574d4df8bf7e4496a876e2930/sort.png)

* Most popular

![Most popular](/uploads/bb92cc2fbef7b6b806dcdf8c52778fdd/most-popular.png)

* Least popular

![Least popular](/uploads/7988ed451922c81dc228419b5edbd7cd/least-popular.png)

See merge request !2781