Adds `jq` command

[zslayton]

Lays the groundwork for an ion jq command.

This PR adds a dependency on the jaq crate, which provides a jq engine, and implements the necessary traits for the Element type.

There are many todo!()s left to implement to support jq features like math operations. However, many basic commands work:

There are plenty of open questions around which jq flags to support, what the default expression should be, etc.

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jobarr-amzn]

Fixes: https://github.com/amazon-ion/ion-cli/issues/41