Create resource tree from WebDAV

[Kaliumhexacyanoferrat]

As the developer of a web application, I would like to integrate resources provided by WebDAV, so that I can easily integrate content hosted there.

Example

val tree = ResourceTree.FromWebDAV(/* url, credentials */);

Host.Create()
    .Handler(Listing.From(tree))
    .Run();

Acceptance criteria

• The functionality is implemented in an additional WebDAV module
• The functionality uses a well tested, mature, maintained library to access WebDAV resources
• Files and folders are fetched on-demand and the information is not cached
• Files are provided by re-using the WebResource (see #125)
• Connections are created and disposed on the fly when needed (resource tree must be thread-safe)
• A connection pool may be used
• Acceptance tests have been written