kmymoney: update ledger icons, fix colorful 32/48 actions' names and placement

Per discussion on #vdg, this intends to add:

• new Panel icons, designed by @mdelafuente, pushing on behalf of him.
• fix the issues with previously added icons, where some colorful icons were being picked up instead of symbolic ones. The fix was to rename the 32/48px versions of:
  • go-home to home
  • view-institution to institution
• move the remaining KMyMoney's side panel icons to actions/32 and actions/48 from preferences folder for consistency