Adding maybe-ubiquity

Changes,

• Fixed the casper-uuid-generic for etiona
• Reduced default boot time to 10 sec.
• Adjust netinst-prepare.sh to be triggered by makeiso.sh and self prepare images.
  • http://ark.switnet.org/tmp/nabia/trisquel-iso-netinstall-working.mp4
• Change behavior to maybe-ubiquity keeping original strings to boot.
• Adding local repository automation for EFI packages.