Include additional scripts in Noto fonts

Generated avatars as well as text file previews are rendered using the
"core/fonts/NotoSans-Regular.ttf" font. The file was the standard hinted
"NotoSans-Regular.ttf" file from https://www.google.com/get/noto/.
However that file does not cover some non LGC (Latin, Greek, Cyrillic)
scripts, like Arabic, Devanagari or Hebrew, to name a few.

Markdown file previews also use "core/fonts/NotoSans-Bold.ttf", which is
in the same situation as the regular one.

Due to limitations in the TTF format it is not possible to provide a
single file for each style that includes all Noto fonts. However, it is
possible to add more scripts to the standard "NotoSans-Regular.ttf" and
"NotoSans-Bold.ttf" files (although no CJK (Chinese, Japanese, Korean)
glyph can be included due to the aforementioned limitations).

This commit replaces the standard files with an extended version created
using the Noto Tools. The build script (as well as a patch for the Noto
Tools) is also included for r...