bcl2fastq by Illumina Elaborate manual with information on manual installation w/o Docker and more options for conversion can be found here:
docker build - < Dockerfile -t bcltofastq
docker run -it -u USER_N -v /directory_of_choice:/data bcltofastq
cd /run_directory_of_your_choice # Should contain RunInfo.xml
bcl2fastq --input-dir /yourdirectory/blabla/Data/Intensities/BaseCalls --output-dir /yourdirectory