Import files from folder as media entities instead of just files

Problem/Motivation

I think it would be better to import files as media entities instead of just files within the system.

Proposed resolution

I noticed that in https://git.drupalcode.org/project/migrate_default_content/-/blob/8.x-2.... the file migration is hard wired to load every file discovered in the target folder as file entities. It would be nice to either have the option to have the migration use a destination of media entity. Maybe two migrations one for file entities, one for media entities.

I can certainly imagine a few use cases where one wouldn't want everything to be media entities (ex: The media module not being enabled). It sure would be nice to have the option to use media.

Remaining tasks

Modify MigrationGenerator::fileMigration to use media entities.