JSON WAF Browser + PHP cURL Engine Test v7

Upload/extract so the root directory is:

json-test/

Main pages/files:
- /json-test/ or /json-test/index.php: single-page UI
- /json-test/php-curl-engine.php: JSON engine endpoint used by index.php
- /json-test/api-test.json: static JSON origin endpoint

Changes in v7:
- Browser tab only shows browser settings and browser results.
- PHP cURL tab only shows PHP cURL settings and PHP cURL results.
- HAR proof steps are their own tab.
- Browser Accept dropdown now includes text/html.
