Add support for dynamic locale

[pixelzoom]

... similar to what was done in phetsims/natural-selection#319.

This also includes geometric-optics-basics.

[pixelzoom]

In phetsims/geometric-optics-basics@633f746, support for geometric-optics-basics was addressed -- it's just the title. That sim has never been published, so has no translations and cannot be tested.

[pixelzoom]

This sim is up next in the list that @kathy-phet gave me, so increasing priority.

[pixelzoom]

Published 1.2.0-dev.2 with brands=phet,phet-io as a baseline before doing this work.

[pixelzoom]

Looks like @zepumph converted some of the strings in this sim, but not others - very inconsistent. And I wasn't aware of this. See 83c1316.

[pixelzoom]

This is done. The only bit that's not supporting dynamic strings in the "Slider Controls" section of the keyboard-help dialog, and that's being tracked in phetsims/scenery-phet#769.

Ready for review by @arouinfar.

[pixelzoom]

Geometric Optics and Natural Selection have roughly the same number of strings (56 vs 55 respectively). But Geometric Optics went a lot faster than Natural Selection phetsims/natural-selection#319 because:
(1) The majority of the Text/RichText instances were already instrumented.
(2) It's in TypeScript, so I got some help from the type-checker, and imports worked in WebStorm.

[arouinfar]

@pixelzoom I reviewed both sims in Studio, and the dynamic locales look great. I didn't encounter any layout issues when editing strings, and everything was nicely instrumented in the view with labelText and titleText which made the strings very easy to find/edit.