novena-firstrun: Run netselect-apt if requested

The mirror will default to the US mirror if unspecified.

Signed-off-by: Sean Cross <xobs@kosagi.com>
novena-firstrun: Set up US Debian sources by default

Without this, we'd use our local apt-mirror, which is not correct.

Since many users are located in the US, set the US Debian mirror.  As a
bonus, this is one of the master servers anyway.

Signed-off-by: Sean Cross <xobs@kosagi.com>
debian: Update package to v1.3

Signed-off-by: Sean Cross <xobs@kosagi.com>