Enable grub/serial tty configuration management (redux)

[vt0r]

• Change default serial port speed to 115200 from 9600
• Update default add_kernel_opts to include ttyS0, ttyS1, and tty1, which seems to be the magic fix for all of our hardware's serial consoles
• Add execute block for update-grub to ensure Grub configs get updated after modifying /etc/default/grub
• Manage service for ttyS* upstart job + force initctl reload config to make sure the changes are actually present before restarting the tty
• This is an Ubuntu 14.04 specific change, due to the upstart management stuff, but only that one block should need modifying for future releases.

Recipe to be included in the proper role(s) as needed.

Revives and then supersedes #806

Still needs to be tested.