use venv for Tensile create on Linux

[TorreZuk]

• if found use virtual env on Linux for Tensile create command match what has been done on Windows
• Utilizes python updates added during initial install, e.g. rocBLAS build

[ellosel]

@TorreZuk have you considered something like this:

https://discourse.cmake.org/t/possible-to-create-a-python-virtual-env-from-cmake-and-then-find-it-with-findpython3/1132

which is cross platform or prepending the TensileCreateLibrary command with:

source /path/to/venv/bin/activate && TensileCreateLibrary

which isn't cross platform but there must be a cross platform way of doing this.

I wasn't sure if we wanted to make these changes here or in virtualenv.cmake in rocBLAS. I personally prefer to let the client control the environment.

[TorreZuk]

@ellosel I first looked at rocBLAS side but as we just call directly the cmake function TensileCreateLibraryFiles this is simpler and it still is the client who sets up the vars/hooks to enable the virtual env use. It also matches what was required and in use windows, so for now think it should suffice unless there are known user conflicts. I assume any cmake defined virtualenv (implicit function argument) would be valid for use here, otherwise it could be a new argument to TensileCreateLibraryFiles.

[TorreZuk]

If this doesn't cause problems would like to merge as need to cherry pick to 6.3 branch to fix installation on new OS.

[ellosel]

Assuming this was tested in an environment where joblib isn't available on the system and only through the venv, I am good with this change.