Improve Java API and Kotlin DSL

[sebastianharder]

• Java: simplify how horizontal and vertical insets can be applied by adding Side.HORIZONTAL/Side.VERTICAL, marginHorizontal()/marginVertical(), paddingHorizontal()/paddingVertical().
• Java: remove necessity to define parameter animated by adding @JvmOverloads
• Java: simplify how inset consumption can be defined: .consume().all() and .consume().auto() instead of .consume(CONSUME_ALL) and .consume(CONSUME_AUTO) (finding the right constants is hard in IDE)
• Java: allow to apply an Insetter to multiple views with just one call: applyToViews(vararg views: View)
• Kotlin: simplify how inset consumption can be defined: consumeAll() / consumeAuto() instead of consume(true) / consume(CONSUME_AUTO)
• Kotlin: add systemBars option as a shortcut for navigationBars + statusBars + captionBar

[chrisbanes]

Hi. Thank you for the contribution, but Insetter has been soft-deprecated for a number of years now. I've just made that clearer in the README and will archive the GitHub repo now.

Feel free to fork the repo if you want to continue development!