DATAJPA-624 - Fix SonarQube warnings as far as possible/reasonable.

Added private constructor to Jpa21Utils to prevent instantiation. Removed unused parameter query in Querydsl.toOrderSpecifier(…). Inline currently unnecessary computeParameterValue(…) method in ParameterBinder. Return cached crudMethodMetadata instead of always creating and caching a new instance in CrudMethodMetadataPostProcessor. Removed unnecessary final modifier from DefaultCrudMethodMetadata. Introduced constant for error message in SimpleJpaRepository as well as for join alias group index in QueryUtils. Prevent instantiation of BeanDefinitionNames by making it an interface instead of a class.

Reduced the usage of EvaluationContextProvider in JpaQueryLookupStrategy implementation. Removed unnecessary fixed sized set initialization in JpaQueryMethod static initializer block. Made JpaResultConverters final since it is not meant to be sub-classed. Avoid potential unsafe reference based equality check in StringQuery/hasPosition(..). Removed dead store in ClasspathScanningPersistenceUnitPostProessor.scanForMappingFileLocations. Encapsulated access to fields in EntityManagerFactoryBeanDefinition.

Original pull request: #114.
DATAJPA-624 - Polished fixes for SonarQube warnings.

Added missing author tag in BeanDefinitionNames. Instead of providing an accessor for EvaluationContextProvider in AbstractQueryLookupStrategy we now only use the property in the type that actually needs it. Removed obsolete method in ParameterBinder. Polished formatting and JavaDoc in EntityManagerFactoryBeanDefinition.

Original pull request: #114.