Add filtering capabilities to Page Builder c-sidebar:
Reuse filtering component here in order to allow users to get to desired block faster.

Design aspects:
Keep same spacing (6px) from the filtering input box to the First group visible, in order to be UI consistent with other filtering input boxes we have in other parts of the UI (see image attached "1_PB Sliders & Blocks.png").

Filtering behavior:
Same filtering behavior should be kept in order to show consistency across the whole application. When the user types a character in the filtering input box, blocks will be filtered up in their groups (see image attached "2_PB Sliders & Blocks.png").