add new key_type table

* single-column static data table that currently contains two types: 'normal' and 'team'
* key_type foreign-keyed from api_keys
  - must be not null
  - existing rows set to 'normal'
* key_type foreign-keyed from notifications
  - nullable
  - existing rows set to null
* api_key foreign-keyed from notifications
  - nullable
  - existing rows set to null

app/schemas.py

@@ -165,6 +165,7 @@ class NotificationsStatisticsSchema(BaseSchema):
 class ApiKeySchema(BaseSchema):
 
     created_by = field_for(models.ApiKey, 'created_by', required=True)
+    key_type = field_for(models.ApiKey, 'key_type', required=True)
 
     class Meta:
         model = models.ApiKey