Enable EL activation expressions when JSF UI is not installed

EL expression evaluation does not depend on JSF so editors for features relying on EL expressions for activation should still be available when JSF UI is not installed (ex: workflow and event listener activation )

TODO
Provide the "custom EL expression" field for:

• Worflows (in the activation tab)
• Event Handlers

HOW TO TEST

• In a project, set up TP LTS 2016 without JSF UI
• Create a workflow, go to the activation tab => custom EL expression field should be visible
• Create an event handler => custom EL expression field should be visible
• Fill in the expression in both fields
• Download the project => custom expressions should be found in the extensions.xml file generated in the bundle