Bundled Themes: Import Twenty Twenty, the new default theme for WordPress 5.3.

Welcome to the bundled themes family!

Theme development to this point has taken place on GitHub. See: ​https://github.com/WordPress/twentytwenty/.

Props anlino, ianbelanger, audrasjb, nielslange, fabiankaegy, mukesh27, poena, joyously, emiluzelac, williampatton, dingo-d, dkarfa, acosmin, rabmalin, kafleg, jeffpaul, hareesh-pillai, burhandodhy, afercia, juanfra, soean, presskopp, justinahinon, jrf, netweb, garyj, pento, flixos90, vbaimas, zebulan, byalextran, mor10, kjellr, allancole, tdh, karmatosed, mapk, matt, andrewtaylor-1, ismailelkorchi, garrett-eclipse, gsayed786, dianeco, celloexpressions, aristath, nadir, cbravobernal, intimez, hometowntrailers, collet, littlebigthing, tobifjellner, kevinkovadia, jarretc.
See #48110.