* Deletes the mmv.model.EmbedFileInfo class file and its test file
* Updates the extension.json and MultimediaViewerHooks.php files to reflect
these deletions (by removing entries from dependency lists)
* Refactors all instances of `new mmv.model.EmbedFileInfo()` to instead use a
POJO with appropriate properties. Conditional assignment is used for the
caption and alt properties if there is any chance they won't be available, to
keep from adding props with falsy values.
* Refactors JSDoc method annotations so that `@param` tags expecting an
EmbedFileInfo instance now expect an object; relevant properties of this
object and their types have been added to the method annotations as well.
Bug: T77320
Change-Id: Ie9f5f24136f4b73000259685474ce4d765a3ccd3
