Mostieri/dvs module

[mariostieriansys]

Add support for a (py)DVS module in PyEnSight.

The module will attempt to load the actual Python bindings from the Ansys install if the connection is local and an Ansys install location is provided, or a folder containing the bindings is provided.
If both are not provided or they don't work (like using a different python distribution), one can provide a PyEnSight session object to use the dvs module on the remote python interpreter where EnSight is running.

The user can also set the session later, since it might be required, for example, if the servers need to be launched in EnSight for an in-situ session.

The module first of all provides the direct DVS api via the stubs coming from ansys-api-pyensight, which switch between pure module or PyEnSight session depending on the availability.
There are also some simplified interfaces that try to hide as much as possible the DVS complexity, helping to start servers, clients, updates, create part and var definition, or sending data. Some simplified assumptions have been done to make the interfaces simple, like the ranks being split evenly among the servers.
For the connectivity array the input is supposed to be the Simba format. While it can be generalized in the future, one can still use the base DVS API to send the connectivity with the "DVS" format

This will be the base for building a "SimbaDVSGraphicsProtocol" to be used in SImba

The PR will fail for the moment being, for two reasons:

1. The ansys-api-pyensight version 0.4.3 doesn't exist yet
2. There is an issue with the CFF reader on linux, that can be reproduced using the latest dev EnSight containers. I guess it is due to the ABI=1 switch. Working on it