Add MPLUS U

[aaronbell]

https://github.com/coz-m/MPLUS_FONTS

"MPLUS U" is an extension to the existing MPLUS family specifically designed for user interface and "universal design" with updated Kana and Latin glyphs (the Kanji are shared with the common set). This will add two new fonts to the MPLUS family on GF: MPLUS U and MPLUS U Code.

• The entire font project is available in a Github repository (repo) and licensed under the OFL
• The source files are available in the repo
• I am the sole copyright author of the entire project, or, all other copyright authors have licensed their work to me under the OFL (@coz-m is the owner)
• There are no "Reserved Font Names" in the OFL license information, or in the project documentation of any known upstream projects. If there are RFNs, they are not used in whole or in part in this family name, or, I want to discuss how Google can work with my use of them.
• The family name is unique according to namecheck.fontdata.com
• The font supports at least the Google Fonts 'Latin Core' glyphset from github.com/googlefonts/glyphsets (direct link)
• The repo has the Google Fonts preferred upstream repo structure
• I have read, agree with, and comply with, the full Google Fonts contributing requirements
• I will maintain the repository and participate in the onboarding process (addressing, solving, and responding to issues, merging pull requests, etc) (@coz-m is the maintainer for the font, I am just assisting with the onboarding process.)