arrow

GH-37917: [Parquet] Add OpenAsync for FileSource (#37918)



### Rationale for this change

Improves performance of file reads with an expensive Open operation.

### What changes are included in this PR?

### Are these changes tested?

### Are there any user-facing changes?
No

* Closes: #37917

Authored-by: Eero Lihavainen <eero.lihavainen@nitor.com>
Signed-off-by: Benjamin Kietzman <bengilgit@gmail.com>