Production board search results index

Currently the search bard of boards is essentially filtering the cards on the board. Overall on mobile this requires the user to then scroll on the board to find the right card. To more easily handle search results and bulk changes to them, we want to introduce:

1. a search result side panel with the matching items listed sequentially
2. a bulk action mechanism that will allow to change stage in groups

This will be initially done specifically for line-items production boards ( Pro plans only ).