git-gui: Make the status bar easier to read in the setup wizard

git-gui: Make the status bar easier to read in the setup wizard

The setup wizard looks better if we layout the progress bar as
two lines:  the first line holds the message text and our text
formatting of the progress while the second line holds the bar
itself.  Both extend the full width of the window and we try to
pad out the message text so the window doesn't expand when the
completed progress number jumps to the next order of magnitude.

This change required updating the progress meter format string
to allow the application to supply the precision.  So we also
are updating all of the translations at once to use the newer
formatting string.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>