Modernize bit-vec benchmarks

[kay-lambdadelta]

This ports the bit-vec benchmarks to criterion

Notes:

• The MSRV of criterion is 1.86.0, instead of the current MSRV of this library (1.85.0).
• What the actual benchmarks do is unchanged, this just changes the benchmarking utility.

[pczarn]

@kay-lambdadelta Thanks, will take a look and send you suggestions if I see anything to correct. We are fine with bumping to 1.86 because it is supported on Ubuntu 22.04 LTS (Jammy Jellyfish) even though it's no longer supported on Ubuntu 20.04.