HashJoinToBindJoinTransformation

• Add interface Transformation that provides the basis for the implementation of equivalence rules used in query optimization.
• Add PhyLeafOperator abstract class that extends BindAccess and provides methods to get and set a string query. All leaf operators will sub-class it (PhyJENAOperator, PhySOLROperator, PhySQLOperator, PhyJQOperator).
• Add reset method in interface DBSourceLayer that allows to reset queries and pagination variables.

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• Add class HashJoinToBindJoinTransformation that transforms PhyHashJoin operators into PhyBindJoin operators. It currently supports Jena, Solr, and SQL as right operators.
• Add class HashJoinToBindJoinTransformationTest that tests PhyHashJoin-to-PhyBindJoin transformations work as expected. It contains tests for Jena, Solr, and SQL as right operators, both with only 1 join column and with 2 join columns.
• Add data sources courses.json (Solr) and professors.ttl (Jena) with two common columns to test joins with multiple columns.

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• Add JSQLparser dependency in POM. It is used in HashJoinToBindJoinTransformation to transform original, unparameterised SQL queries of PhyHashJoin operators into SQL parameterised queries in PhyBindJoin operators.
• Bump version of project to 1.0.1.