Tweaks from UX review

[mlwilkerson]

• [x] Add conditional logic to stopping the timer
• [x] Make Troubleshoot tab active when linking people
• [x] Switch the None case to be really none
• [x] Make the seconds not seem like minutes for the last minute
• [x] Fix duplicate scanner box when shown on the Troubleshoot tab
• [x] Fix state management of conflict scanner box when restarting it from the Troubleshoot tab
• [x] Move the Save button outside the white box
• [x] Add "Remove" column with checkboxes for each and an All affordance (like the Block column)