add endpoint to delete user_individuals

[priesgo]

This adds an endpoint to delete entries from table user_individuals

DELETE localhost:5000/user-individual

Payload:
[
    {
        "user":"test_creation3",
        "internal_id":"PH00008635"
    },
    {
        "user":"test_creation3",
        "internal_id":"PH00008636"
    }
]

Error conditions:

• the payload has other MIME type than JSON
• any of the entities in the payload does not exist
• any other user than Admin

NOTE: I tested this manually using Postman, I didn't know how to add a test on a method that requires a payload in the request (ie: a POST or DELETE method). Any hint on how to do this? I see this FixApi has some support for this but I could not find an example on how to use it.

[pontikos]

This looks good to me, let me know if you want me to merge?

[priesgo]

It is fine for me.