Cleanup junk patterns (empty/default)

[lottehime]

There are a few empty or default texture patterns in the database due to people uploading them to the sites/tools they are dumped from.

There is a detector in my dumping code, but if there are a few pixels different from the default, or from being empty then they will not be rejected by it.

For example:
P001_00_Patrn

They need to be cleaned up manually.

Good first issue for a collab to tackle. I will get to it eventually - but it's low priority 🔻.