Replace fs-extra readJson with JSON.parse of readFile

Replaces fs-extra's readJson/readJSON and readJsonSync/readJSONSync with JSON.parse of readFile from node:fs/promises or readFileSync from node:fs. An awaited call becomes JSON.parse(await readFile(file, 'utf8')), any other promise use readFile(file, 'utf8').then(JSON.parse). An encoding passed as a string or {encoding} is kept. Calls passing throws, reviver, or other options, and callback-style calls, are left alone. Unlike fs-extra, JSON.parse does not strip a leading byte order mark.