[SQM/luci-app-sqm] Enable sqm initiscript if a single sqm instance gets enabled

[SQM/luci-app-sqm] Enable sqm initiscript if a single sqm instance gets enabled

The SQM gui has confused its users with an enable button, that only served to
selecively activate/de-activate sqm instances instead of controlling sqm's
initscript (which needs to be enabled so the sqm properly starts up after a reboot
and also for hotplug to work properly). luci-app-sqm will now enable sqm's
initscript when a single sqm instance get enabled. It also informs the user about
this fact in the top margin of the sqm page. Note sqm will not disable the
initscript behind the user's back if sqm instances get disabled.
While I would have prefered this notice to be more prominent an attentive user
should notice, and most users should not care anyway. This also increases the
package release number.

Signed-off-by: Sebastian Moeller <[email protected]>