Add justify option in editor

[virgile-dev]

Feature Request

Is your feature request related to a problem or unsupported use case? Please describe.
As a user, I want to be able to justify my text.

Describe the solution you'd like
Add the option on the editor.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Discovery, Documentation, Adoption, Migration Strategy
The justify option is supposed to be native in BlocNote.js : https://www.blocknotejs.org/docs/editor-basics/default-schema#default-block-properties

This is especially important for users who want to export the doc.

Pointers by Yousef (blocnote.js)

impress/src/frontend/apps/impress/src/features/docs/doc-editor/components/BlockNoteToolbar.tsx

Line 17 in 50891af

{getFormattingToolbarItems(blockTypeSelectItems)}

-> this is where you add the formatting toolbar buttons. By default, they don't include a button for "justify", so you'd have to add that yourself
e.g.: <TextAlignButton textAlignment={"justify"} key={"textAlignJustifyButton"} />,