PXE installer should inform users that it's installing

[jdreed]

Users are often eager to reboot machines that don't display a login screen. The PXE installer should, after installation begins, change to another VT and throw up an message saying "This machine is being installed, please come back later". Possibly using figlet, for maximum visibility.

[kaduk]

It may be a good idea to include some text along the lines of "installations are expected to take [several|3-5|...] hours", to give a sense for how long it is "normal" to see this message.

[geofft]

For pony points, use the framebuffer (which is already enabled at this point in the installer) to display a pretty picture. There appears to be a command fbi in the fbi package to display an image on the framebuffer, but I think you can also just cat an appropriately-formatted raw image to /dev/fb0 (I recall the Eee initscripts doing this).

Also, note that #702 will get us an actual progress bar, but this should by no means block on #702.

[jdreed]

Is there any reason this is harder than shipping a text file with suitable ASCII art and "openvt -s -- cat whatever.txt"? (Do we have openvt at that point, or do we need to chroot to the installed system?)

I don't really want to block on using the framebuffer.

[jdreed]

Committed in r25150

[cilantro]

Deployed 7 July 2011.