Minor fixes & improvements

Description

Replace Tooltip on buttons with only icon with title. Tooltip caused an infinite loop when tabbed to and crashed the page
Add missing translation
Do not crash if name of system user is somehow null
Add new component for displaying list of rights
Disable save and delete buttons while systemuser is saving or deleting (to prevent sending multiple requests)
Fix property name mapping after changes in bff
Remove link to edit systemuser (PUT and DELETE not working yet)

[ ] Your code builds clean without any errors or warnings
[ ] Manual testing done (required)
[ ] Relevant automated test added (if you find this hard, leave it and we'll help out)
[ ] All tests run green

[ ] User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)