* Add profiler body class on initial load, and respect skipped/complete status.
* Handle PR feedback: Remove unnecessary global, add some todos, added a filter around the next step slug, generalized the is-loading class a bit.
* Add onboarding plugin installation (step 2)
* Handle PR Feedback: Fix vertical label display on mobile, fix Jetpack connect URL generation, so we make sure the plugin is active first, add new constant for local calypso development, fix typo, refactor activatePlugin/installPlugin on the JS side, sanitize plugin name input.