fix: drop configurable appName (#4931)

lib/config/app-strings.ts

lib/config/definitions.ts

lib/platform/github/index.ts

lib/platform/utils/pr-body.ts

lib/workers/branch/index.ts

lib/workers/global/index.ts

lib/workers/pr/body/config-description.js

lib/workers/pr/body/notes.js

lib/workers/repository/error-config.js

lib/workers/repository/finalise/index.js

lib/workers/repository/finalise/validate.js

lib/workers/repository/master-issue.js

lib/workers/repository/onboarding/branch/check.ts

lib/workers/repository/onboarding/pr/base-branch.ts

lib/workers/repository/onboarding/pr/config-description.ts

lib/workers/repository/onboarding/pr/errors-warnings.ts

lib/workers/repository/onboarding/pr/index.ts

lib/workers/repository/onboarding/pr/pr-list.ts

lib/workers/repository/process/index.js

renovate-schema.json