#28)

* perf(internal/bits): Significantly speedup bitArray.PickRandom (backport cometbft#2841) (cometbft#2887)

This PR significantly speeds up bitArray.PickRandom which is used in
VoteGossip and BlockPart gossip. We saw for a query serving full node,
over an hour, this was a very large amount of RAM allocations. (75GB of
RAM!)

![image](https://github.com/cometbft/cometbft/assets/6440154/755918a5-0cef-4e67-a47e-ce8a56aa1cd5)

This PR drops it down to 0 allocations, and makes the routine 10x faster
on my machine.

OLD:
```
BenchmarkPickRandomBitArray-12           1545199               846.1 ns/op          1280 B/op          1 allocs/op
```
NEW:
```
BenchmarkPickRandomBitArray-12          22192857                75.39 ns/op            0 B/op          0 allocs/op
```

I think the new tests I wrote make this more tested than the old code
that was here tbh, but pls let me know if theres more tests we'd like to
see!

---

- [x] Tests written/updated
- [x] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [x] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [x] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec
<hr>This is an automatic backport of pull request cometbft#2841 done by
[Mergify](https://mergify.com).

---------

Co-authored-by: Dev Ojha <ValarDragon@users.noreply.github.com>
Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

* fix failing test

* changelog

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Dev Ojha <ValarDragon@users.noreply.github.com>
Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>
(cherry picked from commit f6abfce)