Multi-Tenant

[AllanGallop]

Adds Multi-Tenant storage

• getTenantID() extended to accept [index] key parameter, defaults to 0
• getTenants() provides currently connected tenants
• store() modified to accept 'tenants' parameter, replacing previous 'tenantId' parameter
• OauthCredentialManger interface modified to suit above changes

Will break any custom UserStorageProviders due to changes in the OauthCredentialManager interface, resolution would be to modify custom providers to match interface.

[hailwood]

Thanks @AllanGallop,

This has been release as 4.0.0 due to the possible bc breaks.
Appreciate your work :)