installer: Install kbd package

A missing `openvt` can lead to the script to fail.

Author: tolbrino

scripts/dappnode_install.sh

@@ -336,6 +336,8 @@ fi
 
 # Run test in interactive terminal
 if [ -f "/usr/src/dappnode/.firstboot" ]; then
+    # ensure openvt is installed prior to using it
+    apt-get install -y kbd
     openvt -s -w -- sudo -u root /usr/src/dappnode/scripts/dappnode_test_install.sh
     exit 0
 fi