LIMS-1396: Use shipping service callback URL to only send emails once shipment is booked

[ndg63276]

JIRA ticket: LIMS-1396

Summary:

Currently, when a user is redirected to the shipping service, Synchweb sends the email and marks the dewar as 'dispatch-requested' instantly, as it doesn't know if/when they have completed the form.
The shipping service now accepts a callback URL, so we can send that in and it will POST to the address with some data about the completed shipment.

Changes:

• Create new non-authenticated endpoint at /api/shipment/dewars/confirmdispatch/did/{dewarid}/token/{token}
• Create pseudo-random token and store in Dewar.extra column as JSON
• Pass callback URL including token to shipping service
• Don't update dewar status and history when first redirecting to shipping service
• Add function at new endpoint to check token, then update dewar status and history, and send email to stores and return lab contact
• Hide email address in dispatch form before redirection to shipping service as it will not be used

To test:

• Make sure $use_shipping_service = True;, $use_shipping_service_redirect = True; and $shipping_service_api_url = "https://sample-shipping-staging.diamond.ac.uk/api";
• Use a dev instance that can send emails (or dump to file as at https://confluence.diamond.ac.uk/x/i_CVCQ)
• Go to a UK shipment, request dispatch without clicking "Use Facility Account", so it doesnt use the shipping service. Fill in the form and submit, check the dewar & shipping status are both dispatch-requested, the history has a line added, but the tracking number has not been filled in (as it doesn't exist). Check an email has been sent immediately.
• Repeat for a non-UK shipment, also without the shipping service
• Now try with a UK shipment and click "Use Facility Account". Click "Proceed" to the shipping service, but before filling in the form, check the shipment in another tab, it should not say dispatch-requested, and no email should have been sent. Now fill in the shipping service form and submit, click "Exit" back to Synchweb and the dewar & shipping status should both be dispatch-requested, an email should have been sent, and the tracking number should be in Synchweb too.
• Check the email carefully, it should have a link to the AWB in the shipping service, check this works.

[NKatti2011]

LGTM