SAML/SSO Support
Currently all objects are tied to some user_id

For companies with many employees this is not desirable. 
SAML/SSO should be introduced with fine-grained permissions per users to allow for example the following case:
Account admin is managing/configuring wallets
Regular employees are only able of checking invoices/marking as complete if needed and no access to wallets page

This is an important feature to make BitcartCC feasible in corporate world