Add IGB display support for CRAM files

[paige-kulzer]

Added a new XML definition file for the CRAM file format and edited the datatypes configuration file accordingly. This enables IGB to appear as a display option when the Visualize icon is selected for CRAM datasets in Galaxy History's.

How to test the changes?

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• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

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