changed tutorial description to html-site instead of string

...ng/kernel/ui/extension/base/TutorialStepUIAtomicBase.java

...kernel/ui/extension/base/TutorialStepUICompositeBase.java

...ension/base/TutorialStepUICompositeWithWhitelistBase.java

...g/kernel/ui/internal/editor/TutorialStepUIDefaultGUI.java

...c/org/fortiss/tooling/kernel/extension/ITutorialStep.java

...rtiss/tooling/kernel/extension/data/TutorialStepBase.java