Auto-link existing IAM accounts

Existing Airlock IAM accounts can have a globally unique attribute that can be used to automatically link a provider's account. To use this feature the property Auto-link IAM Account Based on Context Data Field has to be set.

For security reasons, this feature should only be enabled for attributes that are globally unique and were previously verified by the IAM registration process (e.g. Self Reg) and the provider's registration process.