Allows domains to forgo giving bitrunners their disk items and spells if that is desired (#78959)

## About The Pull Request

Adds two variables to bitrunner domains, one for making them not spawn
disk items, and one for making them not grant disk abilities to
bitrunner characters on loading into the domain.

Not presently used in any domains, but will be a mystery tool that will
help us later.
## Why It's Good For The Game

I've thought of a few pretty good domains but the ideas behind them fall
apart a bit of joey bitrunner can bring a desword and fireball into
them.
## Changelog
🆑
code: Bitrunner domains can now have spells or items from disks disabled
if the domain maker wants such a thing
/🆑

---------

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

code/modules/bitrunning/virtual_domain/virtual_domain.dm

@@ -20,6 +20,10 @@
 	var/filename = "virtual_domain.dmm"
 	/// Any outfit that you wish to force on avatars. Overrides preferences
 	var/datum/outfit/forced_outfit
+	/// If this domain blocks the use of items from disks, for whatever reason
+	var/forbids_disk_items = FALSE
+	/// If this domain blocks the use of spells from disks, for whatever reason
+	var/forbids_disk_spells = FALSE
 	/// Information given to connected clients via ability
 	var/help_text
 	// Name to show in the UI