Adds search filter for Settings on iOS, native iOS keyboard support

[rbreaves]

Description

Greatly simplifies the ability for iOS users to search Settings for the exact setting they are needing to change.

[hizzlekizzle]

Just skimming over this, it doesn't look like much of it is iOS-specific, right? So it should be pretty easy to add to other platforms?

tagging @warmenhoven as the iOS subject matter expert, in case he hasn't seen it already

[rbreaves]

Yea - it shouldn't be iOS specific - but I have only tested it on iOS. I do plan to test this on Android soon, but I have not done so yet as I have not yet compiled it for Android locally to test.

I also just did a force push on it as well as I updated the commit to also include a blinking caret on the search field to make it more obvious that the Search field has focus and is waiting for user input. As well as detection for when they move away from the Settings page so the ios keyboard can automatically re-hide itself. Hopefully it works on Android already, but I cannot confirm that. I am sure it would work with minor additions if not.