Improved job posting flow and packages page

The post a job button now sends recruiters directly to the job posting flow without asking them to select a package.

If your job board has more than one active employer product, we now display a link to the packages page in the navigation bar.

Finally, we updated the look and feel of the packages page. We separated job post credits into a different tab which is displayed only when credits are available, and made visual enhancements to the package cards. We will of course be keeping an eye on conversion rates.