Add new API t3lib_befunc::helpTextArray and use it in the ExtDirect tooltips
Currently the ExtDirect which fetches the tooltip fetches the information on its own from the $TCA_DESCR array. It will also render "TYPO3 Inline Help" as a default header if none is given and will not render an "arrow" which used to symbolize a link to a popup in its content.
This patch adds a new API function t3lib_befunc::helpTextArray which is then used by t3lib_befunc::helpText and also the new ExtDirect call to fetch the information. The tooltips now won't have a title anymore if there is no "alttitle" defined.
Almost none CSH uses "alttile", so usually you won't see any. There are some examples in the Extension manager (e.g. the main titles "Loaded Extensions" etc).
(issue imported from #M16074)