Presign urls for a particular object version

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**

Using AWS S3 it is possible to GET an object with a particular version id. Likewise, it is possible to presign an url for shared access to that object version. `object_store` does support GETting an object version, but does not support presigning an url to a version of an object.

**Describe the solution you'd like**

A new API (probably somewhere in `Signer` trait?) that takes an optional version id along with the `Path`?

Bonus questions: Would you accept a PR to this effect? Could it be S3-specific?

**Describe alternatives you've considered**

Alternatively, make more of the `Signer` / `AwsAuthorizer` machinery public. If `AwsAuthorizer::sign` was public, I could try to hack the version id into the url passed for signing.

Start by reading the Signer trait and AwsAuthorizer::sign, which the issue identifies as the likely API and signing entry point. Compare the existing object-version GET support with presigning, and determine whether the version-id parameter belongs in a general API or an S3-specific path. Done means a decided API can presign access to the requested object version.

Written by the indexing model from the issue text.