Import shipments from CSV file and create temp table from permits

This pull request has a finished task (importing shipments) and a work in progress task (importing permits)

## Importing missing geo entities which are on lib/files/former_and_adapted_geo_entities.csv

To import missing geo entities you can just run:

rake import:unusual_geo_entities

You must also run:

rake import:names_for_trade


## Importing shipments:

We have two types of shipments import:

  ### First time import

  There are some fixes to the original table that must be done in the beginning. To do this run:
  
  rake import:shipments[path/to/file.csv]

  Unfortunately the shipments & permits csv files are too big to store in github. Please ask me for them.


  ### Other imports

  Whenever you want to add new shipments to trade_shipments table you can run:
  
  rake import:first_shipments[path/to/file.csv]

## Importing permits

The import permits script populates trade_permits table and updates trade_shipments origin_permits_ids, import_permits_ids and export_permits_ids).

To run:

  rake import:trade_permits[path/to/file.csv]

## NOTE

Some data seems to be missing. I have listed all the problems that we had during the import on:

 doc/shipments/problems_with_shipments_data.md