Update variable/API terminology to not use "Resolution"

Problem/Motivation

Follow up from 📌 Terminology update: don't say "Resolution" when we mean "Dimensions" Fixed -

Splitting the variable / API changes to a separate issue was recommended by @xjm in #122 so that seems like a good way to proceed here.

Steps to reproduce

Proposed resolution

Update variable/API terminology to not use "Resolution"

Remaining tasks

TBD

User interface changes

TBD

API changes

TBD

Data model changes

TBD

Release notes snippet

TBD