Adds a shortcut to system equalizer. (Only works on android)

[Y0ngg4n]

Added a check if system is android

[jmshrv]

This isn't too useful imo, the user can get to their equaliser in their system settings. If I ever get around to #177, we could likely implement an equaliser in Finamp that will support all platforms

[Y0ngg4n]

Most People dont know about the system Equalizer. I dont know how we could implement it for all platforms.

[jmshrv]

If my plans to use GStreamer as a player backend work, we could implement it in the player: https://gstreamer.freedesktop.org/documentation/equalizer/index.html

Another thing to note is that not all Android skins have a system equaliser, and from quick look at the Equalizer package it looks like there isn't a way to determine this.

[Y0ngg4n]

ah ok thank you :)

[Y0ngg4n]

But i guess there is no gstreamer package we can use so we have to implement it our selves right?

[jmshrv]

Yeah, my initial idea is to make a just_audio implementation that uses GStreamer. It's pretty far off, but it'll be really nice once it's done.