TDP Shared Directory Announce and Acknowledge

[ibeckermayer]

This PR creates a feature branch directory_sharing and merges in the Shared Directory Announce and Shared Directory Acknowledge functionality.

Shared Directory Announce is handled by a Rust function called from Go named handle_tdp_sd_announce.
Shared Directory Acknowledge is sent via a Go function called from Rust named tdp_sd_acknowledge.

I've also broken what was formerly rdpdr.rs down into a multi file module, with the main chunk being in rdpdr/mod.rs. This prevents rdpdr.rs from becoming cluttered with large bitflags and constants structures. Right now its primarily struct representations of RDP messages and the client itself. Note that many of the RDP messages are as of now unused.

There is a webapps branch named isaiah/stub-directory-sharing which this can be tested against. It gives you a big crazy looking "Share Fake Directory" button on the far right of the top bar:

When you click that, expect the session to fail and you should see in the logs something like

[2022-05-03T23:37:58Z DEBUG rdp_client::rdpdr] sending new drive for redirection: ClientDeviceListAnnounceRequest { device_count: 1, device_list: [DeviceAnnounceHeader { device_type: RDPDR_DTYP_FILESYSTEM, device_id: 2, preferred_dos_name: "testing123", device_data_length: 11, device_data: [116, 101, 115, 116, 105, 110, 103, 49, 50, 51, 0] }] }
[2022-05-03T23:37:58Z DEBUG rdp_client::rdpdr] got ServerDeviceAnnounceResponse: ServerDeviceAnnounceResponse { device_id: 2, result_code: 0 }
[2022-05-03T23:37:58Z DEBUG rdp_client::rdpdr] ServerDeviceAnnounceResponse was valid
2022-05-03T19:37:58-04:00 WARN [WINDOWS_D] Failed reading RDP output frame: RDP read failed: RdpError(RdpError { kind: InvalidData, message: "got unsupported major_function in DeviceIoRequest: IRP_MJ_CREATE" }) client-ip:::1 desktop-addr:172.16.97.186:3389 desktop-name:WIN-JR2L4P7KN15-teleport-dev rdp-addr:172.16.97.186:3389 rdpclient/client.go:250

and the browser logs should log an object

{
    directoryId: 2
    err: 0
}

This is indicative that the tdp Shared Directory Announce was translated into an RDP ClientDeviceListAnnounceRequest (handle_tdp_sd_announce), then the server's RDP ServerDeviceAnnounceResponse was translated into a TDP Shared Directory Acknowledge (at which point the RDP server sent an IRP_MJ_CREATE request which is not yet supported, causing the session to fail).

Apologies for this relatively large PR. A big chunk of it is RDP messages that we will need, but don't use in the code yet, and are straightforward implementations from the RDP spec. This is a feature that can really only show anything that works once its implemented end to end. My plan from here is to create a PR for each MajorFunction, starting with IRP_MJ_CREATE, and implementing the logic as described in the RFD (open to feedback on this approach).

[ibeckermayer]

v10 backport #13628