refactor: provide a reference from structs where possible

[dariusc93]

What this PR does 📖

• provide a reference from structs where possible

Which issue(s) this PR fixes 🔨

Special notes for reviewers 🗒️

Additional comments 🎤

• This would reduce needless cloning in Identity, and other structs, thus reducing allocation where possible
• May still require cloning the data where the content needs to be owned.