Add a block toolbar to the editor

Description: Add a block toolbar to the editor to make it easier to move content around. Also, add some basic editing tools to the block toolbar so that the workflow of editing a single block is faster.

Demo of how it should work: https://ckeditor.com/ckeditor-5/demo/editor-types/#balloon-block

Relevant documentation: https://ckeditor.com/docs/ckeditor5/latest/getting-started/setup/toolbar.html#block-toolbar

Acceptance Criteria:

• Editor has block toolbar functionality.