Add a builder for DynamicLayout and switch TextView to it

The builder mostly copies the structure and the logic of
StaticLayout.

We also improve various parts of code and documentation in
StaticLayout's builder.

Bug: 28963299
Test: bit FrameworksCoreTests:android.text.
Test: bit FrameworksCoreTests:android.widget.TextViewTest
Test: bit CtsTextTestCases:*
Test: bit CtsWidgetTestCases:android.widget.cts.TextViewTest
Test: bit CtsWidgetTestCases:android.widget.cts.EditTextTest
Change-Id: I5c4a6e031bd0f41f765a3d85e0b9b7e9be42ad4b