gkeys-gen: Initial migration to use gkeys.base.CliBase class

Add a new gkeys-gen specific config file extension to gkeys.conf.
Change gpghome to use the configured gpg-home setting.
Remove default SPEC and GPG_CONF settings, use configured ones.
bin/gkey-gen update exit.
gkeys-gen: Add spec option

Action config changes
gkeygen/actions.py: Py 3 fixes

Both downloads in py3 are byte strings.  Need to decode them.
Change the "No password given" messages.
Add a logger.eror message with the GpgmeError received.