[otpgen.sh] review security aspects

[shatadru]

• Do not store secret in plain text
  blocked by [RFE][otpgen.sh] encrypt the secret instead of plain text file. #3
• Ask if user wants to delete the QR code as it is not good idea to leave the QR code from which secret can be extracted
  blocked by [otpgen.sh]check if user wants to delete the image after key added successfully #11
• Root user can use strace to read user secret using a script like

#!/bin/bash
#hack user secret
while(true);do
	pid=$(ps aux|grep -i otpgen/otpgen.sh|grep -iv grep|awk '{print $2}')
	if [ -z "$pid" ]; then
	continue
	else
	break
	fi
done
strace -ttTvf -s 1024 -o /tmp/strace -p "$pid"

• the only option is to use shc to create encrypted binary this can be generated during installation and re-generated during clean-install.
• Also there should be easy option given to re-generate the binary either if any changes are made by user or script is updated.

[shatadru]

#11 fixed

[shatadru]

#3 fixed