bug 1066058; add Support Reason API crashstorage type

*Preamble: This PR is primarily submitted for discussion purposes (I expect more work to be necessary).*

This adds the `SupportReasonAPIStorage` class which is a sub-class of `BotoS3CrashStorage`; functionally speaking, the former is basically a *highly lossy* implementation of the latter.

cc @twobraids 
Now we're missing something like this:
```python
report = {
    'uuid': 'abc',
    'classificiations': {'support': { 'bla': 'no classification'}
}
boto_s3_store.save_processed(report)
```