Remove letters-related code (#175)

This deletes a big ol' chunk of code related to letters. It's not everything—there are still a few things that might be tied to sms/email—but it's the the heart of letters function. SMS and email function should be untouched by this.

Areas affected:

- Things obviously about letters
- PDF tasks, used for precompiling letters
- Virus scanning, used for those PDFs
- FTP, used to send letters to the printer
- Postage stuff

app/v2/notifications/notification_schemas.py

@@ -1,9 +1,4 @@
-from app.models import (
-    NOTIFICATION_STATUS_LETTER_ACCEPTED,
-    NOTIFICATION_STATUS_LETTER_RECEIVED,
-    NOTIFICATION_STATUS_TYPES,
-    NOTIFICATION_TYPES,
-)
+from app.models import NOTIFICATION_STATUS_TYPES, NOTIFICATION_TYPES
 from app.schema_validation.definitions import personalisation, uuid
 
 template = {
@@ -48,7 +43,7 @@ get_notification_response = {
         "line_5": {"type": ["string", "null"]},
         "line_6": {"type": ["string", "null"]},
         "postcode": {"type": ["string", "null"]},
-        "type": {"enum": ["sms", "letter", "email"]},
+        "type": {"enum": ["sms", "email"]},
         "status": {"type": "string"},
         "template": template,
         "body": {"type": "string"},
@@ -75,8 +70,7 @@ get_notifications_request = {
         "status": {
             "type": "array",
             "items": {
-                "enum": NOTIFICATION_STATUS_TYPES +
-                    [NOTIFICATION_STATUS_LETTER_ACCEPTED + ', ' + NOTIFICATION_STATUS_LETTER_RECEIVED]
+                "enum": NOTIFICATION_STATUS_TYPES
             }
         },
         "template_type": {
@@ -216,60 +210,3 @@ post_email_response = {
     },
     "required": ["id", "content", "uri", "template"]
 }
-
-post_letter_request = {
-    "$schema": "http://json-schema.org/draft-07/schema#",
-    "description": "POST letter notification schema",
-    "type": "object",
-    "title": "POST v2/notifications/letter",
-    "properties": {
-        "reference": {"type": "string"},
-        "template_id": uuid,
-        "personalisation": personalisation
-    },
-    "required": ["template_id", "personalisation"],
-    "additionalProperties": False
-}
-
-post_precompiled_letter_request = {
-    "$schema": "http://json-schema.org/draft-07/schema#",
-    "description": "POST precompiled letter notification schema",
-    "type": "object",
-    "title": "POST v2/notifications/letter",
-    "properties": {
-        "reference": {"type": "string"},
-        "content": {"type": "string"},
-        "postage": {"type": "string", "format": "postage"}
-    },
-    "required": ["reference", "content"],
-    "additionalProperties": False
-}
-
-letter_content = {
-    "$schema": "http://json-schema.org/draft-07/schema#",
-    "description": "Letter content for POST letter notification",
-    "type": "object",
-    "title": "notification letter content",
-    "properties": {
-        "body": {"type": "string"},
-        "subject": {"type": "string"}
-    },
-    "required": ["body", "subject"]
-}
-
-post_letter_response = {
-    "$schema": "http://json-schema.org/draft-07/schema#",
-    "description": "POST sms notification response schema",
-    "type": "object",
-    "title": "response v2/notifications/letter",
-    "properties": {
-        "id": uuid,
-        "reference": {"type": ["string", "null"]},
-        "content": letter_content,
-        "uri": {"type": "string", "format": "uri"},
-        "template": template,
-        # letters cannot be scheduled
-        "scheduled_for": {"type": "null"}
-    },
-    "required": ["id", "content", "uri", "template"]
-}