python3: merge python3-email into python3-urllib

As we're seeing in various test.sh scrip runs, importing 'email' fails
with not finding 'urllib' and vice-versa.

Then via a7e96ec91 ("python3-email: add python3-urllib as dependency")
I created a circular dependency.
So, might as well merge the two packages into one (named python3-urllib)
and updates all dependencies to pull python3-urllib.

Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>

lang/python/python-cryptography/Makefile

@@ -35,7 +35,6 @@ define Package/python3-cryptography
       +libopenssl \
       +libopenssl-legacy \
       +python3-light \
-      +python3-email \
       +python3-urllib \
       +python3-cffi \
       $(RUST_ARCH_DEPENDS)