Can't clear messages that are over 14 days old

[s0lst1ce]

Describe the bug
It is not possible to delete the messages over 14 days old using the clear command.

Steps to reproduce
Try to use the `clear command on messages over 14 days old.

Expected behavior
Being able to delete any message

Additional context
This is due to the limitation of the bulk delete method of the API. Bulk deletes are not supported for messages over 14 days old.
Since bulk delete does improve performance by a lot it should be kept. However a failsafe method for messages over 14 days old should be used automatically if bulk delete fails.