Create an ION to Morphir Reader.

**Is your feature request related to a problem? Please describe.**
[Amazon Ion](https://amazon-ion.github.io/ion-docs/) is a data format that is used heavily in the AWS ecosystem, it would be beneficial if we could read Ion models in and produce Morphir models from that.

**Describe the solution you'd like**
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**Describe alternatives you've considered**
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**Additional context**
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