Refs #15288 Fix merge issues

.github/CONTRIBUTING.md

.github/PULL_REQUEST_TEMPLATE.md

.gitignore

CMakeLists.txt

Framework/API/CMakeLists.txt

Framework/API/inc/MantidAPI/AlgorithmFactory.h

Framework/API/inc/MantidAPI/AlgorithmHistory.h

Framework/API/inc/MantidAPI/AnalysisDataService.h

Framework/API/inc/MantidAPI/BoxController.h

Framework/API/inc/MantidAPI/ConstraintFactory.h

Framework/API/inc/MantidAPI/EnabledWhenWorkspaceIsType.h

Framework/API/inc/MantidAPI/Expression.h

Framework/API/inc/MantidAPI/FunctionFactory.h

Framework/API/inc/MantidAPI/GeometryInfo.h

Framework/API/inc/MantidAPI/GeometryInfoFactory.h

Framework/API/inc/MantidAPI/IFunction.h

Framework/API/inc/MantidAPI/IMDHistoWorkspace.h

Framework/API/inc/MantidAPI/IMDNode.h

Framework/API/inc/MantidAPI/IMDWorkspace.h

Framework/API/inc/MantidAPI/ImplicitFunctionParser.h