Epic: Implement OpenShift Serverless Functions workflow in OpenShift Toolkit for IntelliJ

[sbouchet]

Implement the OpenShift Serverless below features into OpenShift Toolkit extension for IntelliJ.

• Add a new node in the navigation with name as Serverless Functions #932
• Update to latest func cli https://github.com/knative/func
• Implement create action
• Implement build action
• Implement run action
• Implement deploy action
• Implement invoke action

[adietish]

According to @mohitsuman's plan we should priotize #924 which seems more urgent for now