Add or change tooltips

[bspekker]

Current behavior
Some icons are missing tooltips.

Wanted behavior

• header bar > link to committee: add tooltip "Go to committee"
• header bar > global search: the global search icon should have the tooltip "Global search"
• Tags (in orga level > tags and in meetings > agenda/motions > tags): all pencil icons should have the tooltip "Edit"
• Tags (in orga level > tags and in meetings > agenda/motions > tags): all bin icons should have the tooltip "Delete"
• Projector menu > Star icon: change to "Sets this projector as the reference for the autopilot and the current list of speakers."
• Projector menu > slideshow icon: Change from "Open projector" to "Open projector in new tab"
• Motions > blocks/categories > number of motions: change the display of the tooltip so it's shown below the number

The tooltip should occure while hovering over the icon, cf existing tooltips.