Added GrassCoverErosionInwardsFailureMechanismResultView. Simplified name of CalculationScenarioStatus. Extracted FailureMechanismSectionResultRow views. Introduced specific failure mechanism classes for every stand alone failure mechanism. Introduced CustomFailureMechanismSectionResult for a section result with a double value for assessment layer 2a. Introduced SimpleFailureMechanismSectionResult for a section result with a enum value for assessment layer 2a. Introduced a CustomFailureMechanismContext and SimpleFailureMechanismContext to be able to serve different views and tree nodes. Related to Issue [WTI-513]