Fast destroy of uploads was successfully enabled and test.

remove_file_uploads should be called both with and w/o
the flag - we need to decide which way to use on instance level.

These options are then used when setting before destroy callback.

Fast destroy is used only if the feature flag is enabled, otherwise
uploads are still deleted using carrier wave. It's disabled by default.

It gathers list of file paths to delete before destroying
the parent object. Then after the parent_object is destroyed
these paths are scheduled for deletion asynchronously.

Carrierwave needed associated model for deleting upload file.
To avoid this requirement, simple Fog/File layer is used directly
for file deletion, this allows us to use just a simple list of paths.

Partially addresses #47424.

This is tricky: the query was being run in
`ObjectStorage::Extension::RecordsUploads#retrieve_from_store!`, but we can't
just add batch loading there, because the `#upload=` method there would use the
result immediately, making the batch only have one item.

Instead, we can pre-emptively add an item to the batch whenever an avatarable
object is initialized, and then reuse that batch item in
`#retrieve_from_store!`. However, this also has problems:

1. There is a lot of logic in `Avatarable#retrieve_upload_from_batch`.
2. Some of that logic constructs a 'fake' model for the batch key. This should
   be fine, because of ActiveRecord's override of `#==`, but it relies on that
   staying the same.

destroy_all loads all records at once

ObjectStore uploader requires presence of associated `uploads` record
when deleting the upload file (through the carrierwave's after_commit
hook) because we keep info whether file is LOCAL or REMOTE in `upload`
object.

For this reason we can not destroy uploads as "dependent: :destroy" hook
because these would be deleted too soon. Instead we rely on
carrierwave's hook to destroy `uploads` in after_commit hook.

But in before_destroy hook we still have to delete not-mounted uploads
(which don't use carrierwave's destroy hook). This has to be done in
before_Destroy instead of after_commit because `FileUpload` requires
existence of model's object on destroy action.

This is not ideal state of things, in a next step we should investigate
how to unify model dependencies so we can use same workflow for all
uploads.

Related to #45425