[Feat] Author tracking system for posts and pages

[Adammatthiesen]

Implement a author tracking system to be able to keep track of current authors and allow an optional checkbox to either display authors and contributors or not to on pages/posts also keeping track of new authors during updates and being able to show them as a stacked list of contributors to the post. These options would be able to be stored as a new json column in the PageData table with a format something like the following:

// `column.json()` from `@astrojs/db` is type unknown and will require a type cast such as the following
type AuthorsTrackingType = {
    authorId: string;
    contributors: Array<{ 
        id: string 
    }>;
    showAuthorOnPage: boolean;
    showContributorsOnPage: boolean;
};

Also in order to not break current installs there would be a check during update that if there is no authorId, then it would add the first editor as the author.