Merge babel-plugin-fbt-runtime into babel-plugin-fbt

[jrwats]

🚀 Merge babel-plugin-fbt-runtime into babel-plugin-fbt

The old behavior of babel-plugin-fbt should be configurable via plugin option and babel-plugin-fbt-runtime should simply be "on" by default.

Motivation

babel-plugin-fbt-runtime being written as a separate plugin is largely due to historical reasons and to Facebook's own internal usage patterns. It's not exactly optimal from an end-user app-developer perspective. Ease the pain, and merge the plugins

Example

A webpack plugin configuration of

            ['babel-plugin-fbt', {
              fbtEnumPath: path.join(__dirname, '.enum_manifest.json')
            }],
            'babel-plugin-fbt-runtime',

would instead look like:

            ['babel-plugin-fbt', {
              fbtEnumPath: path.join(__dirname, '.enum_manifest.json')
            }],

FB usage of the babel-plugin-fbt Babel transform would be called via:

            ['babel-plugin-fbt', {
              fbtEnumPath: path.join(__dirname, '.enum_manifest.json')
              fbtSuppressRuntimeTransform: true,
            }],

or via some better named boolean.

Pitch

2 plugins is 1 too many. Some might argue, 2, too many.