Introduce smb_traffic_analyzer protocol v2.

Introduce smb_traffic_analyzer protocol v2.

From Holger:
Make smb_traffic_analyzer differ the protocol versions to enable the development of version 2 of the protocol. To do this, a new parameter "protocol_version" has been introduced, which can be set to "V1", "V2", or nothing. If protocol_version is not set, V1 will be chosen automatically.

Created an enum for identifying VFS functions in the upcoming protocol v2. Converted the existing VFS functions to use the identifier, and set the read/write bool used in protocol v1 accordingly, also ignore any other VFS functions except read/write/pread/pwrite in v1. Added a first new VFS function for mkdir, which I use for testing and implementing both the sender and receiver for v2.