feat: consolidate entities create

This was done to give better typings to the function signatures of entities `create` methods.
It also ensures that each field that should be set to `null` is set to `null` and doesn't leave that up to the typeorm handlers.

See: #1641
Signed-off-by: Philip Molares <philip.molares@udo.edu>

src/media/media-upload.entity.ts

@@ -59,7 +59,7 @@ export class MediaUpload {
     extension: string,
     backendType: BackendType,
     backendData?: string,
-  ): MediaUpload {
+  ): Omit<MediaUpload, 'createdAt'> {
     const upload = new MediaUpload();
     const randomBytes = crypto.randomBytes(16);
     upload.id = randomBytes.toString('hex') + '.' + extension;