Create shipments

Made this a WIP pr cause it's getting too big and don't want it to become overwhelming to review.

done so far: crud for shipments end to end.

To be done:

1. Get receiving group to see shipment
2. if group doesn’t exist send email to email account given
3. Change db schema to have sender_address and receiver_address as actual addresses from our Adress module. This will allow viewing on the map and better planning of routes
   • 2a. create two more forms so flow goes create_shipment -> shipment_details ->sender_address-> receiver_address
4. full route plan(viewing on map?)
5. unit tests
6. allow for multiple groups to be sender or receiver (change group_id to list if possible, if not make it a string and split group_ids by comma to get all groups involved)

design choices: Db design was intentionally made to be independent of everything else to keep us flexible as we figure out what groups want from this feature. Once we figure it out, can reduce what they need to type to create a shipment and start coupling things, reducing the verbosity/explicitness.