Support signing up with organization membership

[nandan-bhat]

🔧 Changes

• A new property is_signup_enabled is added to the organization connections.

🔬 Testing

Create a config.json file similar to:

{
    "AUTH0_DOMAIN": "<YOUR_DOMAIN>",
    "AUTH0_CLIENT_ID": "<CLIENT_ID>",
    "AUTH0_CLIENT_SECRET": "<CLIENT_SECRET>",
    "AUTH0_INCLUDED_ONLY": ["organizations"],
    "AUTH0_ALLOW_DELETE": false
}

Use the following commands to import or export configs.

Export yaml: node lib/index.js export -c config.json -o ./local -f yaml
Import yaml: node lib/index.js import -c config.json --input_file ./local/tenant.yaml

is_signup_enabled is exported.
is_signup_enabled is imported on creation.
is_signup_enabled changes to existing enabled connections are detected and it is updated.

Important use-cases related to this change:

• is_signup_enabled is valid only when the strategy is auth0. i.e is_signup_enabled will not available in non db connections.
• is_signup_enabled can be set to true only when assign_membership_on_login is set true. However, you can set is_signup_enabled to false when assign_membership_on_login is set to false.

Continue the same test or json format as well.

🔬 Change Verification

• With this PR changes, is_signup_enabled property value can be manipulated and changes can be seen on the auth0 dashboard.

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[developerkunal]

Changes looks good to me.