CSV importer fixes

Features
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* Catching field errors so we can pass a more descriptive error to the user
* Allowing location__name to filter fields for SystemRacks.
* CSS animation during CSV processing
* Green gradient added to new fields

BUGS
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* Renamed _get_dict_related and _get_pk_related to get_realted_from_dict and get_related_from_pk. These names seem more accurate.
* Renamed header to raw_header. raw_header is more accurate since it hasn't been parsed yet.
* system_model should have been server_model
* ServerModel should have been Allocation
* Made sure all examples in the documentation worked
* Fixed white space trimming around headers