Added argument to include loose hits in the heatmap

[Louis-MG]

Loose hits are now possibly included in the heatmap using the argument --include_loose. Their color is purple and black now represents no hit.

./rgi heatmap -i tests/outputs/NC_020818.1.json -o tests/outputs/heatmap_test_to_remove
./rgi heatmap -i tests/outputs/ -o tests/outputs/heatmap_test_to_remove_loose_hits --include_loose
./rgi heatmap -i tests/outputs/ -o tests/outputs/heatmap_test_to_remove

Produces:


This might be useful for exploration purpose (e.g. environment that is not well characterized). This was not vibe coded.