Using Maple 18.02 in Windows 7 64bit, the closet I could get was to use densityplot instead of listdensityplot (so the "grid" lines appear thinner in the GUI, since the latter produces a bunch of polygons...).

restart:
export_plot_options:=font=[TIMES, roman, 30],
axis=[thickness=4, location=origin],
size=[850,850]:
P:=plots:-densityplot(exp(-(x^2+y^2)*(1/100)),
x = -10.0 .. 10.0, y = -10.0 .. 10.0,
export_plot_options,
grid=[21,21], scaling=constrained):
subsop([1,1]=0..21.5, subsop([1,2]=0..21.5, P));

[edited] I posted the above in the early morning. I now realize that the obscure double subsop step could be replaced by a single call to plots:-translate. Ie,

restart:
export_plot_options:=font=[TIMES, roman, 30],
axis=[thickness=4, location=origin],
size=[850,850]:
P:=plots:-densityplot(exp(-(x^2+y^2)*(1/100)),
x = -10.0 .. 10.0, y = -10.0 .. 10.0,
export_plot_options,
grid=[21,21], scaling=constrained):
plottools:-translate(P, 10.5, 10.5);

Having done that, I now reazlie that the originally posted example can be handled the same way, using location=origin and a translation. Ie,

restart:
export_plot_options:=font=[TIMES, roman, 30], axis=[thickness=4, location=origin], size=[850,850]:
points := [seq([seq(exp(-(x^2+y^2)*(1/100)), x = -10.0 .. 10.0)], y = -10.0 .. 10.0)]:
P:=plots:-listdensityplot(points, export_plot_options):
plottools:-translate(P, -0.5, -0.5);

Of course, if you don't like the ranges 0..21 then you could adjust to taste. I'm not really sure whether you wanted axes' ranges from -10..10, or 0..21, or 0..21.5, etc. Or you might ecen want go with densitplot and no translation, as it produces a nicer looking (to me) plot with less obtrusive gridding, and contains an efficient float[8] rtable rather than many list data polygons.