Add a mechanism to get ions version

Created by: BafDyce

Expected behavior: It would be great if ion would provide some mechanisms to retrieve some version information about the binary. e.g. via help about or ion --version This information could include a "fixed" version such as 1.0.5 Alpha and/or the latest commit hash when the binary was compiled, as well as (optional) the systems' version.

This is especially helpful during development to quickly check if one runs the "new" version or not.

Actual behavior: Currently, ion does not provide any mechanism to retrieve its version.

Misc: To be honest, I don't know how hard it is to retrieve the latest commits hash at compile time. Another useful addition would be to display additional information such as the current (at compile time) branch and whether there were unstaged changes.