Legal API - Create endpoint for retrieving stage 1 AR letter

[argush3]

Create an endpoint that will be used by the emailer to retrieve the stage 1 letter(notice of commencement of dissolution) to be used as email attachment. Note that this endpoint will be used to retrieve the stage 1 letter for a one business. A separate ticket will take care of generating the batch stage 1 letters that will be sent to BCMail+.

Url structure of new endpoint

GET <base_url>/businesses/<business_identifier>/furnishings/<id>/document
Content-Type: application/pdf
Accept: application/pdf

Although we have a separate endpoint for generating furnishing documents, it will still leverage the existing report generating code that is already available in the legal api.

One major difference to note is that the letter will need to follow BCMail+ formatting requirements. If these requirements are not met, there may be printing issues on their end.

Reference PPR repo for reference BCMail+ implementation. The repo contains an implementation for generating a cover letter + main content report as well as code for SFTP upload. Note that a cover is not required for this ticket.

TODOs

• Implement GET endpoint(GET <base_url>/businesses/<business_identifier>/furnishings//document) which returns a BCMail+ compatible AR pdf version of letter. Note: some updates around address may be still pending design updates. check with Andy to see where things are at before starting work. Should still be able to start work even if pending design updates though.
• Add units tests as appropriate

PPR code reference - https://github.com/bcgov/ppr/blob/94dd475c3b657c88c35ab33922f5d540b64b6fb8/ppr-api/src/ppr_api/resources/v1/callbacks.py#L36-L76

[vishnup0422]

Using the endpoint to retrieve the PDF doc for a business

Retrieving the greyscale doc for mailing

If the business is registered in Extra Provinces

When the Business ID is not correct

When BusinessId and FurnishingID are not matching.