streams: Implement BitStreamReader/Writer classes.

Summary:
Golomb-Rice coding, as specified in BIP 158, involves operations on
individual bits. These classes will be used to implement the
encoding/decoding operations.

For BIP158; is cherry-picked from two commits (fe943f9 and 9b622dc) from:
https://github.com/bitcoin/bitcoin/pull/12254/commits

Depends on D2797.

Test Plan: make check

Reviewers: #bitcoin_abc, deadalnix, Fabien

Reviewed By: #bitcoin_abc, deadalnix, Fabien

Subscribers: Fabien

Maniphest Tasks: T589

Differential Revision: https://reviews.bitcoinabc.org/D2799