Adding option to automatically installation

This extends FindPystencilsSfG.cmake with a Cache Variable CODEGEN_PRIVATE_VENV. This is set by default and if activate it creates a python venv and installs either dependencies from a requirements.txt or if this is not present it downloads the latest pystenicls-sfg/pystencils versions. If a custom Interpreter is passed to cmake this deactivated.

In external CMake Projects this files could by included via

## Pystencils-sfg setups
set(FIND_PYSTENCILSSFG_CMAKE_PATH "${CMAKE_BINARY_DIR}/_pystencilssfg-cmake/")
file(DOWNLOAD
    "https://i10git.cs.fau.de/ob28imeq/pystencils-sfg/-/raw/cmake_setup/src/pystencilssfg/cmake/FindPystencilsSfg.cmake?ref_type=heads"
    "${FIND_PYSTENCILSSFG_CMAKE_PATH}/FindPystencilsSfg.cmake"
)

SET ( CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${FIND_PYSTENCILSSFG_CMAKE_PATH})

find_package( PystencilsSfg REQUIRED )

requested review from @da15siwa

assigned to @ob28imeq

I've given this some more thought, and I think the find-module is the wrong place for the venv setup. CMake semantics indicate that a Find module should merely discover an existing installation of a package, and not download and build that package - which is effectively what we are doing.

Instead, I'd suggest we provide a small standalone Cmake project (basically just a CMakeLists.txt) which exposes the venv-functionality. This would also simplify inclusion into downstream projects using FetchContent, something like:

FetchContent_Declare(
    PystencilsSfg
    URL https://i10git.cs.fau.de/pycodegen/pystencils-sfg/-/jobs/artifacts/master/raw/CmakeStandalone.tar.gz
)

FetchContent_MakeAvailable( PystencilsSfg )

The above would pull the CMake project from CI artifacts. Once we start releasing pystencils-sfg, we can provide this CMake project with fixed dependency versions via a GitLab Release.

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• 4bd3aa7f - Moved the bootstrapping of a pystencilssfg installation to another file

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• b38d5f6a - added a ci job to make standalone cmake files available

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• 510cadf6 - fixed typo

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• 6eec7958 - Apply 1 suggestion(s) to 1 file(s)

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• cd06d247 - Apply 1 suggestion(s) to 1 file(s)

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• c1058bdb - also calling cmake make-find-module on custom python venvs

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resolved all threads

approved this merge request

We'll need a short getting-started guide for this, but considering the changes I made in !21 (merged), we should probably set up a separate MR for it.

mentioned in issue #13

merged

mentioned in commit 25ad35e8