Use Pippenger multiplication for combining multiple sigs of same msg

[etan-status]

Newer blst releases expose multiscalar Pippenger multiplication that allows accelerated verification of signatures pertaining to same msg.

• https://gist.github.com/wemeetagain/d52fc4b077f80db6e423935244c2afb2

[etan-status]

• Needs https://github.com/status-im/nim-blscurve/pull/178

[github-actions[bot]]

Unit Test Results

         9 files  ±0    1 334 suites  ±0   30m 18s :stopwatch: -6s   5 064 tests ±0    4 716 :heavy_check_mark: ±0  348 :zzz: ±0  0 :x: ±0  20 991 runs  ±0  20 587 :heavy_check_mark: ±0  404 :zzz: ±0  0 :x: ±0 

Results for commit 574a99dd. ± Comparison against base commit 231c41ea.

:recycle: This comment has been updated with latest results.