Show hints for standard JPA properties

Enabling JPA facet on a project generates the following persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="helloworld">
</persistence-unit>
</persistence>

Adding <property> to <properties> should show hints for standard JPA properties. So a cursor placed within " and " for name should show all the standard JPA properties that are available. And may be even provider-specific properties as well.

<properties>
<property name="" value=""/>
</properties>

This will provide a simpler experience for developers.