thinkpad: remove various assumptions

* hardware.trackpoint.emulateWheel = true; is very biased, this module
  is only for ThinkPads anyway, so default value should be used
* All options that should be overridable (e.g. services.tlp.enable)
* Hardware profile should not pull in stuff into system environment
  unless it's hardware-specific (pkgs.acpi is not)
* sound.mediaKeys clashes with DE, e.g. Xfce handling sound keys
* Drop redundant synaptics.enable = false;