Ability to create "Subscription" manually without a Payment link

[Razem]

Currently "Subscriptions" for contacts or companies are created when a buyer makes a purchase using a payment link configured to collect recurring payments, or a quote integrated with payments that includes recurring line items.

It would be great to provide the ability to create a subscription manually – for those who want to track subscriptions but do not necessarily use HubSpot to process a payment. 

In our case, we want to track subscriptions for subscribers paying via invoice.

Or import existing subscriptions without requiring customers to go through the HubSpot Payment process.