[gdal_rasterize] Also accept doubles for -ts

[elpaso]

But warn if it has a decimal part.

Fixes #11829

[jratike80]

Out of curiosity, what will be the output size when the input is -ts 100.4 200.6?

[elpaso]

Out of curiosity, what will be the output size when the input is -ts 100.4 200.6?

The same as -ts 100 200 internally casted to int (but you'll get a warning the precision was lost).

[jratike80]

If the price of one beer is 8.2€ but you have only 8, would you ask the bartender
"Is it OK if the conversion to int looses precision for the price parameter"?

How about "Warning: The value of the -ts parameter gets truncated into [lower] integer"?

[coveralls]

coverage: 70.055% (-0.008%) from 70.063%
when pulling 5be98e8 on elpaso:bugfix-gh_11829-gdal_rasterize-be-good-accept-double
into 6332083 on OSGeo:master.