Add several QtWebKit WebActions

Add WebActions ToggleBold, ToggleItalic, ToggleUnderline,
ToggleStrikethrough, AlignLeft, AlignCenter, AlignRight,
AlignJustified, Indent, Outdent, InsertOrderedList and
InsertUnorderedList.
All use the javascript document.execCommand with
parameters according to
https://developer.mozilla.org/de/docs/Web/API/Document/execCommand



Task-number: QTBUG-59221
Change-Id: Ife18d660fefa2073351c5ad959611ec47b680dc6
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>