arrow

ARROW-9947: [Python] High-level Python API for Parquet encryption of files.

Exposes in PyArrow the high-level C++ API for Parquet encryption that was added in https://github.com/apache/arrow/pull/8023.
Design document:  https://docs.google.com/document/d/1i1M5f5azLEmASj9XQZ_aQLl5Fr5F0CvnyPPVu1xaD9U
A test is added for writing and reading encrypted parquet files using a simple in-memory KMS for testing, that is not to be used as an example of a KMS client. In addition, there is an example KMS client using Vault KMS.

This PR handles only the file-level encryption and decryption.
Dataset is handled in separate PRs.
The investigation of the multithreading model of PME is separated into a separate issue, independent of this one.

Closes #10450 from andersonm-ibm/encryption

Lead-authored-by: Maya Anderson <mayaa@il.ibm.com>
Co-authored-by: andersonm-ibm <63074550+andersonm-ibm@users.noreply.github.com>
Co-authored-by: roee88 <roee88@gmail.com>
Co-authored-by: Antoine Pitrou <antoine@python.org>
Signed-off-by: Antoine Pitrou <antoine@python.org>