[FIX] 0042349: UI Tooltips (via Topics) won't shown on slate-triggerers in MainBar

[chfsx]

as mentioned in https://mantis.ilias.de/view.php?id=42349, Slates currently are unable to receive UI-Topics which are needed for e.g. the Tooltips of the Help-Package to be rendered correctly (@alex40724 this might be of interest for you).

I implemented the HasHelpTopics interface in Slates with this PR. Please be aware that this might break some layouts when using Topcis, but as far as I can see the e.g. Buttons inside a CombinedSlate inside the MetaBar are broken anyway (look strange since some time)., I sure it will be easier for people which are fitter than me in (S)CSS to takle this in one step.

A central question is, of course, which component receives the tooltip in the case of a slate (the same question probably arises for all components that internally use another component, for example, as a trigger, i.e. something like Modals). From this point of view, tooltips can be said to be at the triggerer. For further use cases (such as extensive explanatory texts), further Purposes should be implemented for the Topics, which then also allow a different form of presentation in a component.

Is there anything needed beside this?