feat: add Divider component

[anonymousRecords]

Description of Changes

Here is reference: #25

---

support 'Divider' block

• add custom solution for rendering 'Divider' block.

Review point

• I used the color rgba(223, 223, 222, 1) for the divider, which I confirmed by capturing it from Notion. Is this approach acceptable?
• In the DividerArgs type definition, I simplified it to only include the type property:

export type DividerArgs = {
  type: "divider";
} & ContextedBlock;

Is this simplification appropriate, or should we maintain the empty divider object for consistency with other block types?

To reproduce

• npm run story:start
• click 'your created block' on the Storybook left side panel

Screenshot

Review Guide

Reviews are conducted based on priority levels, such as p0, p1, p2, p3, p4, and p5.
p0 ~ p2: If the author decides not to reflect a review for p0 to p2, it signals that a proper discussion with the reviewer is
necessary. It is expected that the review will be resolved either through incorporating the feedback or through further discussion.
p3: indicates that the reviewer has identified a significant issue, but either lacks a clear solution or the comment lacks sufficient context. Further explanation or additional discussion on the reviewer's concerns is needed.
p4, p5: p4 and p5 suggest low priority, and if the author does not deem them important, these comments can be disregarded.

[Moon-DaeSeung]

LGTM