Feature/pixi and conda installation

[Tobiaspk]

Closes #18

Tested installation instructions on Linux with CUDA 12.1 with simplified setup with pixi or conda:

Note: CUDA 12.2 should be compatible with the CUDA 12.1 installation.

git clone https://github.com/dpeerlab/segger.git
cd segger

# with pixi
pixi install -e cuda121

# with conda
conda env create -f environment_cuda121.yml -n segger

Please feel free to test and add more.