Allow pbix to read its own filepath

[marcos_t]

Please enable PowerBI to identify its own filepath so we can use this as a parameter when pointing to datasources stored in the same folder. This will allow us to move the pbix from one folder to another and the data source will automatically be repointed to the new folder. Very useful for businesses with standard pbix reports that are used for multiple clients, projects etc. I note Excel has a simple formula to identify its own path which is SourceFilename = ThisWorkbook.Path so perhaps PowerBI can replicate this functionality