Support private git repositories

Nextflow can access private Git Repositories by storing credentials in the SCM Configuration file.

CloWM could save the file in the params buckets with the following structure

providers {
    <workflow_id> {
        user = 'your-user-name'
        password = 'your-personal-access-token'
        server = 'https://github.com'
        platform = '<github|gitlab>'
    }
    ...
}

• Creating Gitlab Deploy Token with the scope read_repository and read_registry if private containers are used from the project
• Creating GitHub Access Token by selecting the right repository and add read-only Contents permission

The SMC File in the params bucket can be referenced with the ENV Variable NXF_SCM_FILE which should be $PARAMS_BUCKET_MOUNT_PATH/scm. The Nextflow command must be changed to

nextflow run <repository_url> -hub <execution_id> ...