Support special directory that can always skip trash

[SandyXSD]

What would you like to be added:
Configure a directory (must be empty?) so that all files created under it will be deleted directly, ignoring the trash.

Why is this needed:
Some application may create a lot of temporary files that should be purged completely no matter the trash is enabled or not.

[SandyXSD]

We may use the special attribute bit that can be set by chattr:

s      When a file with the 's' attribute set is deleted, its blocks are zeroed and written back to the disk.

[mcassaniti]

Another reasonable option is to use a user extended attribute. Would a PR be welcome?

[zhijian-pro]

@mcassaniti Getting extended Attributes is an additional metadata overhead

[mcassaniti]

@zhijian-pro Forgive my naivety, from what you're saying an extended attribute check would require extra DB reads of metadata just to check attribute values during a delete? Do these records need to be touched during a delete currently? I'm guessing no but it pays to check.

Honestly I didn't think about the extra overhead. If the chattr approach is best then I'm happy to look into a PR if the project is willing to take one?