fix: second round audit - backup paths, cleanup, dead code

CT scripts:
- ct/hoodik.sh: backup to /opt instead of /tmp
- ct/pixelfed.sh: backup to /opt, add CLEAN_INSTALL=1
- ct/skylite-ux.sh: backup to /opt instead of /tmp

Install scripts:
- install/alpine-install.sh: add missing cleanup_lxc
- install/ubuntu-install.sh: replace manual apt-get cleanup with cleanup_lxc
- install/debian-install.sh: apt-get -> apt
- install/hoodik-install.sh: remove 40 lines of dead commented code
- install/step-ca-install.sh: remove  from export builtins

install/step-ca-install.sh

@@ -24,8 +24,8 @@ msg_info "Installing step-ca and step-cli"
 $STD apt install -y step-ca step-cli
 
 STEPHOME="/root/.step"
-$STD export STEPPATH=/etc/step-ca
-$STD export STEPHOME=$STEPHOME
+export STEPPATH=/etc/step-ca
+export STEPHOME=$STEPHOME
 
 $STD sed  -i '1i export STEPPATH=/etc/step-ca' /etc/profile
 $STD sed  -i '1i export STEPHOME=/root/.step' /etc/profile