Replace &Option<T> with Option<&T>.

[HaoYang670]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Actually, I file this issue because I just remember we've ever done the same thing in arrow-rs: apache/arrow-rs#1556
And I find a discussion about the trade-off between &Option<T> and Option<&T>: https://www.reddit.com/r/rust/comments/wqsxk2/is_it_better_to_pass_optiont_or_optiont/

Describe the solution you'd like
A clear and concise description of what you want to happen.
It isn't the goal to replace all the occurrences of &Option<_>, but to do the replacement if we can benefit from it.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.
We could not do this

Additional context
Add any other context or screenshots about the feature request here.

[tustvold]

I can't think of a valid reason to ever return &Option<T>, so 👍