v1.5.0: Update Calcite to 1.26, add @super, @className, @classLoader

Added

• Extra property for all objects: @class (references to java.lang.Class)
• Extra property for all objects: @className (returns the name of the class)
• Extra property for Class objects: @classLoader (references to java.lang.ClassLoader)
• Extra property for Class objects: @super (references to java.lang.Class)

Changed

• Eclipse Memory Analyzer 1.8.0 or higher is required
• Java 1.8 or higher is required
• Update Apache Calcite to 1.26.0 (see https://calcite.apache.org/news/2020/10/06/release-1.26.0/)
• Update Guava to 29.0-jre

Fixed

• name for IClass return class name rather than the value of Class.name field (OpenJDK uses the field as a cache, so it might be null)
• Declare reference columns as nullable, so the engine does not optimize count(name) into count(*)