Bundle the *Last Resort High-Efficiency* font from
https://github.com/unicode-org/last-resort-font/
version 13.001 (Oct 22 2020).
This provides a more useful fallback glyph than we'd otherwise
produce if there is no matching glyph in any of the fonts.
Its license is OFL-1.1 which is compatible with the other
bundled fonts.
These serve two purposes:
* Provide a consistent default font for new installations,
that happens to show off ligature and color emoji support
out of the box.
* Provide a reasonable fallback in case the configuration is broken
Both fonts are distributed under the terms of the OFL 1.1.
refs: https://github.com/wez/wezterm/issues/263
