Add aar file to cordova plugin

[Moonlight448]

@jcesarmobile

se lib-file tag instead of resource-file tag for copying the .aar file, and remove the whole the gradle file as it’s not needed.

See an example on barcode plugin https://github.com/phonegap/phonegap-plugin-

Thank you for your help:pray:
Problem solved by changing
flatDir{
dirs ‘src/main/libs’
}