feat: make `ionic cordova resources` comply with Android O adaptive icons

[eikooc]

Hello. This is a feature request for Android O - Adaptive icons integration with the ionic-cli.

Make the ionic resources cli command able to add the necessary information and convert an extra background file or extract an background layer from a .psd file to be able to use the new Adaptive icons in Android O.

[RafaelKr]

Hi, I really would love to see this feature. Is this already on the roadmap?

[captaincole]

Hey guys, just backing up these claims. Would really appreciate this so my icon looks great with the pixel and pixel 2.

[steveacalabro]

+1

+1

[nicksalt]

+1

[ElieSauveterre]

+1

[robinbonnes]

+1

[askilondz]

+1

[danicastanos]

+1

[herrskytte]

+1

[jaclynjessup]

+1