refactor(user): Deprecate Signin, Verify email and Invite v1 APIs

[ThisIsMani]

Type of Change

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

Description

This PR will remove the following endpoints and corresponding APIs
/user/signin
/user/verify_email
/user/invite

Additional Changes

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

Motivation and Context

Closes #4464

How did you test it?

curl --location 'http://localhost:8080/user/signin' \
--header 'Content-Type: application/json' \
--data '{
    "email": "user email",
    "password": "password"
}'

curl --location 'http://localhost:8080/user/verify_email' \
--header 'Content-Type: application/json' \
--data '{
    "token": "email token"
}'

curl --location 'http://localhost:8080/user/user/invite' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer JWT' \
--data '{
    "email": "email",
    "name": "name",
    "role_id": "merchant_view_only"
}'

When these curls are hit, BE will respond with 404 Not Found with the following body

{
    "error": {
        "type": "invalid_request",
        "message": "Unrecognized request URL",
        "code": "IR_02"
    }
}

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