feat(plugin-blog): multi-authors support + authors.yml global configuration (#5396)

* Complete function

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* A lot of blank lines

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* More lenient validation

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Remove or

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Simpler logic

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Expand docs

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Better docs

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Dogfood

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* More writeup

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Polish

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Polish

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Move mergeAuthorMap to authors.ts

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Unbreak relative assets

* Update docs

* Clarify in docs

* simplify feed authors

* rename authorMap -> authorsMap

* mergeAuthorsMap -> getBlogPostAuthors

* website => 5 blog posts per page

* improve authors map file

* Extract new theme authors components + display in row

* add comment for meta array syntaxes

* blog => getPathsToWatch should watch authorsMap file

* remove useless v1 blog FBID frontmatter

* keep older frontmatter syntax for now

* revert blog frontmatter

* Better console message

* better blog authors frontmatter impl

* add multi authors to beta blog post + fix some authors margins

* fix React key

* Refactor: mdx loader should support a more flexible assets system (poc, not documented yet)

* better display of blog post authors: adapt layout to authors count + add line clamp

* smaller local image

* fix blog feed tests

* fix blog frontmatter tests + improve validation schema

* add more frontmatter tests

* add tests for getAuthorsMapFilePath

* tests for validateAuthorsMapFile

* add tests for readAuthorsMapFile

* test getAuthorsMap

* exhaustive tests for getBlogPostAuthors

* fix remaining tests

* missing blog plugin author tests

* fix windows tests

* improve blog multi-author's doc

* Use new format in init template

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* Improve error message

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* update feed snapshot

* blog authors: limit to 2 cols + fix margins for no authors

* minor doc improvements

* better init template blog posts, demonstrating Blog features

* replace the legacy blog author frontmatter in remaining places

* Prefer using clsx

Signed-off-by: Josh-Cena <sidachen2003@gmail.com>

* cleanup getColClassName

* remove blog author name/title line-clamping

Co-authored-by: slorber <lorber.sebastien@gmail.com>

website/docusaurus.config.js

@@ -270,7 +270,7 @@ const TwitterSvg =
             }
             return `https://github.com/facebook/docusaurus/edit/main/website/${blogDirPath}/${blogPath}`;
           },
-          postsPerPage: 3,
+          postsPerPage: 5,
           feedOptions: {
             type: 'all',
             copyright: `Copyright © ${new Date().getFullYear()} Facebook, Inc.`,