Use B (Billion) instead of G (Giga) for non-byte sizes

Description

In some reports where numbers are displayed (for example - rows count) we display G for Billion like GiB for size numbers. Now we fixed it, so simple (not size) numbers are displayed as B (billon), T(Trillion), q(Quadrillion) etc.

Related issue

https://gitlab.com/postgres-ai/postgres-checkup/issues/438

Examples

[present examples for reviewers: new CLI output, screenshots, etc]