feat(users): Add transfer org ownership API

[ThisIsMani]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

This PR will add a new api to transfer ownership of an organization to other.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

To allow users to change the ownership of an organization.

How did you test it?

Postman

curl --location 'http://localhost:8080/user/user/transfer_ownership' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer JWT of org_admin user' \
--data-raw '{
    "email": "email of the user who is not org_admin"
}'

If the api is successful, it will return the following response.

{
    "token": "JWT",
    "merchant_id": "merchant_id",
    "name": "name of old org_admin",
    "email": "email of old org_admin",
    "verification_days_left": null,
    "user_role": "merchant_admin"
}

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible
• I added a CHANGELOG entry if applicable