refactor: replace qLowerBound & qUpperBound with std:: upper_bound & lower_bound

Summary: This is a backport of Core PR16674 - https://github.com/bitcoin/bitcoin/pull/16674

Test Plan:

ninja check

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, deadalnix, jasonbcox, nakihito

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, jasonbcox, nakihito

Subscribers: jasonbcox

Differential Revision: https://reviews.bitcoinabc.org/D4722