bmpblk: Update bitmaps for two-column footer

Update the footer bitmaps for the new two-column footer layout:

- Add the generic "Enter" string for the Enter keycap, in the new
  keycap style.
- Add the volume up, volume down and power icons from Google Symbols
  for the keycaps on detachables. Build them only for detachables, and
  build "Enter" only for the other devices.
- Update the footer and footer_nav styles for the 18px text in the new
  design: set the height to 21 (18 * LINE_HEIGHT_RATIO), and update
  max_width to fit the new column widths.
- Move rec_url to the new footer_url style, because max_width is not
  allowed for generic strings. Draw it in the primary color (#A8C7FA),
  as in the design.
- Regenerate qr_rec white on black without the quiet zone, so that
  depthcharge can recolor it and draw the quiet zone as the padding of
  the box around it. Shrink qr_rec to 86, the size of the code in the
  new design.

The column headers in the design ("How to navigate with keyboard" and
"More details") need new localized strings, which will be added
separately.

BUG=b:551743258
BRANCH=none
TEST=BOARD={geralt,rauru,staryu} make
TEST=DETACHABLE=1 BOARD=geralt make
TAG=agy
CONV=4d411a1c-369f-4fd3-ac8a-7bd726afa3b5

Cq-Depend: chromium:8500034
Change-Id: Ib051caf5f5b5d91409fdb18d47d43972fd8cbfb0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/bmpblk/+/8499997
Reviewed-by: Chen-Tsung Hsieh <chentsung@chromium.org>
Commit-Queue: Yu-Ping Wu <yupingso@chromium.org>
Tested-by: Yu-Ping Wu <yupingso@chromium.org>
GitOrigin-RevId: a201ec5331340e6e12b1c327508a01bfd3c88e5e