An SD printing progress bar for ULTRA LCD screens

First commit of untested code to print a progress bar in the status
region of the status display. This implementation only shows the
progress bar if the current lcd_status_message starts with a colon. In
the final version it will alternate between progress bar and the
message every few seconds (unless the message is empty or starts with a
colon).
Tweak comment, test commit
Replace some custom chrs to get progressbar chrs

Since we can only define 8 custom characters, replace some of the less
essential ones with good enough substitutes.
Leave out unused char bitmaps.
Keep the clock, flash current message

The “refresh” character is much more rare, so restore the clock and
replace “refresh” with the infinity symbol. If there is a message,
alternate it with the progress bar every 2 seconds, or so.
Make sure message is displayed quickly

If the status message changes the progress bar should disappear for a
second or two.
Minor optimization, fix the tick variable.
Narrower bar so it looks more… intentional
Group progress-bar bitmaps together and loop.
Use millis() and add PROGRESS_BAR_INTERVAL

Better timing of the status message blinking, based on the millisecond
clock.
Disable the progress bar option by default.
More accurate doc, other Configuration_adv.h
Progress bar without sacrificing glyphs

Added a hook so that custom characters can be set whenever the LCD menu
changes. Using this, the progress bar characters are only set for the
Info Screen, while the regular glyphs are used for submenus. Supporting
changes simplify the code quite a bit.
Allow tuning of bar and message time separately
Add message expire options, move timing code

Messages can now be set to show for a time then hide instead of
blinking, and they can be set to clear after a period of time (when the
progress bar is visible). Timing processing moved so it will be occur
more often.
Set message time for PGM strings too
Tweak comment, test commit
Make sure message is displayed quickly

If the status message changes the progress bar should disappear for a
second or two.
Use millis() and add PROGRESS_BAR_INTERVAL

Better timing of the status message blinking, based on the millisecond
clock.
Disable the progress bar option by default.