Spoqa Han Sans: A custom font based on Noto Sans and Lato

This is Spoqa Han Sans JP, which supports both Korean and Japanese but
prioritizes Japanese Kanji above the other.

"Spoqa Han Sans is a custom font based on Noto Sans and Lato to fit
multilingual UI of Spoqa's products. We now unveil the new version which has
evolved in many ways."

• Spoqa

WWW: https://github.com/spoqa/spoqa-han-sans

• poudriere (11.2-, 12.0-RELEASE, 13.0-CURRENT@r345355 amd64 + i386) -> OK (with options ORIGINAL/SUBSET on/off each)
• portlint -> OK
• Runtime tests by using deskutils/gucharmap -> OK

Minor fixes from the original patch:

• Sorted variables a bit according to the PHB
• Simplified the installation by using option helpers to use custom variable SRCFONTSDIR