- rename methods with XML to Xml, CRS to Crs, WMS to Wms, ID to Id
- rename methods with SRS to Crs
- rename methods with abbreviations like "dest" to "destination"
- rename methods with abbreviations like "src" to "source"
The original name was not representative for the scope of the class
and misleading at best.
The class manages actions for a given layer and it's not a single action
like the former name suggested.
There is a typedef introduced to keep it in the API until we can remove
it with QGIS 3.