Record sorting

[eito-fis]

Fixes #158

Adds the option to sort the values returned from the record list endpoint.

Technical details
Modifies records.get_records() to use our fork of sqlalchemy_filters for sorting, and adds handling for the order_by url parameter to the record list endpoint.

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[eito-fis]

This should be reviewed after #299 is merged.

[kgodey]

This seems fine to me, I'll also leave it to @mathemancer to review once #299 is reviewed.

[mathemancer]

I think this looks good.