Add ParquetObjectReader::with_runtime (#6248)

[tustvold]

Which issue does this PR close?

Closes #6248

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[alamb]

I am depressed about the large review backlog in this crate. We are looking for more help from the community reviewing PRs -- see #6418 for more

[alamb]

Thank you @tustvold -- the idea here looks great. I think what we need to do now is to add some sort of test (maybe a doc example or something) showing how to use this and it would be good to go

[wiedld]

Thank you @tustvold -- the idea here looks great. I think what we need to do now is to add some sort of test (maybe a doc example or something) showing how to use this and it would be good to go

@tustvold -- do you mind if I take this over, adding docs & tests?