streams: Create VectorReader stream interface for vectors.

Summary:
This is a read analogue for the existing CVectorWriter.

For BIP158; is cherry-picked from two commits (947133d and 87f2d9e) from:
https://github.com/bitcoin/bitcoin/pull/12254/commits

In addition, the buggy seek() method was removed per later backport:
https://github.com/bitcoin/bitcoin/pull/14357

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/D2797