Issue-74: Add Gutenberg Block(s) to render Bylines for Full Site Editing

[llflannery]

Summary

Fixes #74

This pull request introduces a new Gutenberg block for Full Site Editing that displays author data from Byline Manager instead of the standard WordPress authors. The block is intended to seamlessly integrate with block themes and be available in the same contexts as the core author block, such as in the post template and query loop blocks. This ensures it can be used on single pages and post listings while maintaining user-friendly customization options.

Changes Made

• Created a Gutenberg block for displaying Byline Manager author data.
• Ensured the block is available in the same contexts as the core author block (e.g., post template and query loop blocks).
• Implemented support for setting attributes, allowing users to leverage options available in the Byline Manager's template tags.

Testing Instructions

1. Add the new Byline Manager block to a post template or query loop block in a Full Site Editing theme.
2. Verify that the block correctly displays author data from Byline Manager.
3. Test customization options (e.g., attributes like "Author," "Show Avatar," "Avatar Size," "Show Bio," "Link Author Name to author page") to ensure they reflect Byline Manager data accurately.
4. Confirm compatibility with single page and post listing contexts.

Additional Notes

• This task builds upon the foundation laid by issue Filter the core author block to replace its data with the data from byline manager  #346, which hijacks the core author block to display Byline Manager data via a PHP filter.
• UI settings in the core author block have been overridden to align with Byline Manager data to avoid confusion.