Specify default file and directory modes for files and directories downloaded from OneDrive

[fishnet37222]

Is your feature request related to a problem? Please describe.
Quite often I use OneDrive to store configuration files that I like to share between the various Linux hosts I have. I find it annoying when I have to manually change a file from mode 600 to mode 644.

Describe the solution you'd like
A setting in the config file would satisfy this request.

Describe alternatives you've considered
I don't believe there are any alternatives, other than using the proprietary ExpandDrive product which seems to have issues running on systems such as Gentoo and Arch.

Additional context
Nothing else to add.

[abraunegg]

@fishnet37222
Please review the usage document - this already exists: https://github.com/abraunegg/onedrive/blob/master/docs/USAGE.md#sync_dir-directory-and-file-permissions