Update the check function to support using the PROPFIND method for checking

[y805939188]

In my scenario, I am unable to use 'disable_check=true' to disable check, but my webdav server does not support using get or head methods to check if a directory exists. Therefore, I hope to support using the propfind method to check the directory.

[l-jonas]

I consider this a duplicate of #129. The other issue that existed before additionally shows why PROPFIND should be used in any case. As a result, I do not consider #143 a solution because it only allows manually overwriting the HTTP verb instead of changing the default.