Expose deleteFile method for external usage

[osevastianovych]

sfcc-ci/lib/webdav.js

Line 67 in 8b4d513

function deleteFile(instance, path, file, token, ignoreLocalFilePath, options, callback) {

Hi @tobiaslohr, I can see that you have nice method for deleting files on instance via webdav but we can't use it in our purposes. It will be nice to have such possibility as part of available webdav api.
So if it possible and you will have time for it please provide us deleteFile webdav api.

Many thanks, Oleksii.