feat(react-tokens): unify react-token generation

[redallen]

What: After consuming our react-tokens package while working on patternfly/patternfly-org#1772 and working towards #4044 I realized our react-tokens had incorrect values in some cases.

#3896 added a new dist/variables folder that always generates correct values, but in a format like this:

{
  c_about_modal_box: {
    ".pf-c-about-modal-box" : [
      {
        "variable "--pf-global--Color--100",
        "value": "#fff",
        "token": "global_Color_100",
        "values": [
          "--pf-global--Color--light-100",
          "$pf-global--Color--light-100",
          "$pf-color-white",
          "#fff"
        ]
      },
    ],
    ".pf-c-about-modal-box .pf-c-card": {}
  }
}

This PR changes the format to this:

{
  c_about_modal_box: {
    ".pf-c-about-modal-box" : {
      "global_Color_100": {
        "name": "--pf-global--Color--100",
        "value": "#fff",
        "values": [
          "--pf-global--Color--light-100",
          "$pf-global--Color--light-100",
          "$pf-color-white",
          "#fff"
        ]
      },
    },
    ".pf-c-about-modal-box .pf-c-card": {}
  }
}

and moves dist/variables to just dist/esm or dist/js. It also now generates the legacy token files like dist/esm/c_about_modal_box__brand_image_Height.js that match the old format from the new token generation:

export const c_about_modal_box__brand_image_Height = {
  "name": "--pf-c-about-modal-box__brand-image--Height",
  "value": "2.5rem",
  "var": "var(--pf-c-about-modal-box__brand-image--Height)"
};
export default c_about_modal_box__brand_image_Height;

so we can have a unified generateTokens.js script now!

Additional issues: Need to go upstream to gatsby-theme-patternfly-org to fix the /documentation/overview/global-css-variables page.

Breaking changes

react-tokens

• Some of our tokens have had their values updated to be correct.
• New files with a different structure have been added to the index.

[patternfly-build]

PF4 preview: https://patternfly-react-pr-4058.surge.sh
A11y report: https://patternfly-react-pr-4058-coverage.surge.sh

[ddonahue007]

LGTM