* nongnu/packages/electron.scm (define-module): Remove no longer
required modules
(electron)[build-system]: Use chromium-binary-build-system.
[patchelf-plan]: Drop it since the build system figures it out from the
wrapper plan;
[wrapper-plan]: New argument;
[phases]: Adjust to chromium-build-system;
[inputs]: Drop the inputs provided by the build system.
Signed-off-by: Jonathan Brielmaier <jonathan.brielmaier@web.de>