Translations:Release notes 0.18/22/en

FEM Workbench
In 0.17 there where added tons of new features in FEM. Thus the main focus for FEM in 0.18 relese of FreeCAD was not adding even more new features and tools, but make the existing ones more stable and fix as much as possible bugs. FEM got 470 commits during FreeCAD 0.18 development cycle.