Provide the khiops-env script for all packages

[bruno-at-orange]

The script khiops-env is designed to be used by pyKhiops to run Khiops with the proper settings concerning java and mpi. It appears that it is not usable in conda environments. It would be "healthy" to use khiops-env in all environments and then we have to provide khiops-env in all khiops packages (conda included).

[bruno-at-orange]

For windows the problem is that khiops-env is generated by the nsis script during the install process. There are two main issues:

• the jre path is discover by scanning the registry
• the process number is set by a nisis function

The first one is no longer a problem because the jre is now vendored with khiops. For the second one, we can get the process number directly in khiops-env by using wmic. Unfortunately, It is a bad solution because wmic is deprecated.

Another solution is to build a little binary to get the process number (in the stdout). Then to package this binary within khiops and to call this binary in khiops-env.