i.sentinel.download: various improvements

[ninsbl]

This PR adds:

• a p-flag for displaying the query send to DHUS
• support for multiple orbit numbers
• better handling of ingestiondate in query
• fix iloc-warnings from pandas
• linting
• improved projection of AOI coordinates

[lucadelu]

Did test but it looks good

[landam]

What is the reason for changing header (comments to multi-line string)?

[ninsbl]

pylint complained about missing module docstring. I am not sure if there is a prefered way for how the module header should be written. I happily change it back if that is prefered...

[landam]

Personally I prefer PyGRASS API. But what is the reason to use it on single place only?

[ninsbl]

I wanted to pipe to stdin of m.proj and use the results in stdout at the same time, see:

grass-addons/src/imagery/i.sentinel/i.sentinel.download/i.sentinel.download.py

Lines 282 to 297 in 4a8e44e

	coord_proj = Module(
	"m.proj",
	input="-",
	flags="od",
	stdin_="\n".join(coords),
	stdout_=PIPE,
	stderr_=PIPE,
	)
	poly += (", ").join(
	[
	" ".join(poly_coords.split("|")[0:2])
	for poly_coords in coord_proj.outputs["stdout"]
	.value.strip()
	.split("\n")
	]
	) + "))"

I am not aware of how to do that in the script API, while I knoew it to work in pygrass. If you have a suggestion for how to do this, I am happy to adjust...