Iss4 - create a way to attach attach items to armor and weapons (#310)

* add basic drag drop window

* add better field

* make effects copy onto actor on attachment

* make items from inventory draggable

* working drop from inventory

* remove duplication issue

* add attachment only flag and logic

* add weapons to attachables

* remove debug logs

* try to make it drier

* remove unecessary try catch

* remove extra configs

* remove superfluous comments

* remove spurious defenses

* make drier

* remove unecessary code

* deduplicate and simplify

* its a desert

* standardize to be more similar to class item code

* fix bug of duplicate effects being created

* fix localization string

* fix bug of item equiping and un equiping

* remove this since were not going to be using attachmentonly

* update attachment tab with comments

* remove attachment only logic in favor of just transfer

* change flags

* change armor and weapon to be attachableItem

* change armor and weapon to be attachableItem

* change weapon to use mixin

* add mixin to armor

* move everything to mixin sheet

* refactor code for review comments

* cleanup and somehow git is ignoring some changes

* see if this picks up the changes now

* Import/Export updates

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Co-authored-by: psitacus <walther.johnson@ucalgary.ca>
Co-authored-by: WBHarry <williambjrklund@gmail.com>

module/config/flagsConfig.mjs

@@ -7,3 +7,5 @@ export const encounterCountdown = {
     simple: 'countdown-encounter-simple',
     position: 'countdown-encounter-position'
 };
+
+export const itemAttachmentSource = 'attachmentSource';