control.tpl: remove python3 Recommends/Suggests

Both of these variables are never used, resulting in build warnings after creating a package with py2dsp. Remove the two unused lines from the template.

I don't feel necessary this change. I think that this remove should be done by the maintainer after run pypi2deb. I appreciate that pypi2deb give me a complete debian/* files possibilities and then, I work in customize the package.

I created this commit because I am tired of removing these two lines each time. I created a lot of packages, and these two lines I think I have never used. Maybe one compromise would be to introduce a "dpt-simple" profile for simple packages that do not recommends nor suggests anything?

That could be a good idea, but to avoid overwork, I'd wait the morph's opinion.

currently there's only a handful of packages using this feature in DPT:

$ grep -l -- --recommends */debian/rules
androguard/debian/rules
beancount/debian/rules
python-canmatrix/debian/rules
rdflib/debian/rules

$ grep -l -- --suggests */debian/rules
beancount/debian/rules
python-azure-devtools/debian/rules

so i agree with removing those lines

merged

mentioned in commit 4c04b1bc