Add extensions for Intent creation

[hluhovskyi]

Make creation of intents easier. Covers #166.
In case if intent is implicit or don't require any application component:

val intent = intentOf(
    action = "action",
    data = Uri.parse(...),
    categories = setOf("category"),
    extras = bundleOf("key" to "value")
)

In case if intent should be created for specific component of application, you can use extension for Context:

val intent = context.intentFor<MyActivity>(
     action = "action",
     flags = Intent.FLAG_ACTIVITY_CLEAR_TASK,
     extras = bundleOf("key" to "value")
)

Possible parameters: action, data, type, categories, flags, extras

Concerns: in case if you need simply start activity with just one extra, it will look a bit massive

startActivity(intentFor<MyActivity>(extras = bundleOf("key" to "value")))