Create desired folder directly from Folder Dialog

[Beebeeoii]

Is your feature request related to a problem? Please describe.
Currently, the FolderDialog seems to lack the feature of creating a new folder to be selected. For example, if the directory /Users/me/ exists, but I want to select the folder /Users/me/folder which does not already exist, I would have to create the folder separately first before selecting it from the FolderDialog.

Describe the solution you'd like
Have a button in the Folder Dialog to directly create a new folder in the current directory.

Additional context
Directly related to issue fyne-io/fyne#3174 and pull request fyne-io/fyne#3178

[Beebeeoii]

This enhancement is taken care of by #67.