Add version field to ExecutionContext

[tfeda]

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

#1514 points out a secondary goal for the python library to expose the datafusion and arrow-rust versions.
I think Spark has a good implementation of this by binding the spark version to SparkContext in the jvm code, then exposing it to the pyspark API. pyspark's version itself is hard-coded.

Describe the solution you'd like

Add a version field to the ExecutionContext struct, and expose it to the datafusion-python library. The version could then be retrieved by users by calling ExecutionContext.version

Describe alternatives you've considered

Leaving it out of the rust implementation and just putting it in the python version.

Additional context
I'm not sure how arrow-rust's version would be added, but a similar approach could be taken.

[tfeda]

I'm new to the project (and open source in general), so I think this would be a good exercise for me. Because it's an API addition, I could use some stylistic input on the solution I proposed above.

[alamb]

What version would you like to appear? Do you have in mind the version of the rust crate https://github.com/apache/arrow-rs/blob/master/arrow/Cargo.toml#L20 ? If so you can probably follow the same model as parquet

Here is how the version is embedded in parquet files 'created by' fields: https://sourcegraph.com/github.com/apache/arrow-rs/-/blob/parquet/build.rs?L20:25&subtree=true

https://stackoverflow.com/questions/27840394/how-can-a-rust-program-access-metadata-from-its-cargo-package