Added the find usages module boilerplate for qmlls and a first implementation to find usages of JS-declared variables. A test was added to tst_qmlls_utils to see if the usages can be found and another one in tst_qmlls_modules to see if the usages are correctly communicated to the language client (with an extra check that uris are passed with their "file://"-prefix from qmlls). Future commits will implement the Find-usages for QmlObject ids, properties and functions (signals, methods, slots, handlers, ...). Added QQmlLSUtils::qmlLocationToLspLocation for convertion from QQmlJS::SourceLocation and QLspSpecification::Range that takes care, among other things, of 1-based to 0-based line and row conversions. Changed the VariableDeclarationEntry to contain a IdentifierExpression, as this allows to find "usages" in the definitions. Adapt the tests to this change. Task-number: QTBUG-100084 Task-number: QTBUG-111415 Change-Id: I3a734f3ccf73fa88ed2f28b65ce2582461965ed1 Reviewed-by: Ulf Hermann <ulf.hermann@qt.io> Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>