Add a https transfer method (sharing all host details with the http
transfer). Make this method the default for all downloads.

Try to make sure the binary pkg installation (which runs in a chroot
in the already installed system) can make use of SSL verification.

This does NOT fix the missing SSL verification in most install media
even if using https (due to not fully populated /etc/openssl/certs).

branches: 1.2.2;
Re-enable the entropy handling code in sysinst (only visible on machines
that do not have full entropy), but move it to the config menu
instead of enforcing it as mandatory step.

This menu is shown at the end of the setup, or if explicitly invoked
from the main menu.

Some of the input options are complex but useful in some situations
and code to support them is tiny. Most users will use the manual input
(first + default option) but some might prefer to connect a USB TRNG
or have easy setups to transfer entropy from another machine (while
copy & paste on a serial console sometimes is tricky).

Add (experimental) entropy input support:
Early during new installs or after upgrades we check if entropy is
available. If not (no hardware random number generator available)
we inform the user and ask them to fix it.