Add scTE option for quantification

[mikecuoco]

Thanks for developing this incredible workflow! Have you considered adding scTE as an option for quantification of genes + transposable element (TEs) expression? The workflow would require (1) building a genome index with genes + TEs and (2) running quantification on a bam file generated by CellRanger or STARsolo. These steps are outlined in detail in the authors' README.