HR-216 - Calculate stored pay estimates

Triggers for calculation:
 * Modifying HRJobPay or HRJobHour
 * Modifying constants
 * Upgrading => HR-1.2
 * Generating example data

Estimates are only calculated if pay_is_auto_est is true
HR-216 - jobtabapp/pay - Add lock icon and placeholder for explanatory message.
HR-216 - jobtabapp/pay - Load "settings" in the controller and inject to the view
HR-216 - jobtabapp/pay - Hide/display message based on whether the lock is enabled
HR-216 - hrreport/test - Add FTE, annual-pay-estimates to fixtures
HR-216 - Update annual cost report to use pay_annualized_est instead of pay_amount

Also:
 * Remove buggy column "hrjob_period_type" (which is displayed but not grouped)
 * Simplify field label
 * Update tests