Merge pull request #1230 from FlowFuse/add-pql-handbook

Add PQL to handbook.

src/handbook/marketing/hubspot.md

@@ -23,6 +23,7 @@ The folowing is a description of each stage.
 | Subscriber | Contact has signed up to hear more information, when it is available, about FlowFuse, e.g. newsletter subscriber |
 | Lead | Contact that has converted on our website, or through some other interaction, with our organisation beyond a subscription sign up. For example, registered for a webinar, signed up for a free trial, etc.|
 | Marketing Qualified Lead | The contact has requested to talk to someone directly at FlowFuse about the product/services of FlowFuse, either through book a demo, contact us, or direct outreach to a FlowFuse employee. Support requests are not considered MQL. |
+| Product Qualified Lead | The Customer success team identifies a contact that they believe is a candidate for an upsell opportunity. Customer success will identify an PQL by monitoring FlowFuse Cloud usage and engaging with these users in a consultative manner. Any contact already identified as an MQL, SQL or Opportunity should not be a candidate for PQL. |
 | Sales Qualified Lead | After the initial discussion with an MQL, the sales team will qualify if the contact is a potential customer by changing the lifecycle stage to SQL. This status of this stage is then further qualified in the [Lead Status](#lead-status) property. |
 | Opportunity | A contact becomes an Opportunity once a Deal has been opened. The [3 W's need to be answered before opening a deal](../sales/#from-sql-to-opportunity)  |
 | Customer | An active, paying, user of FlowFuse. |