Refactor Buff Ending Announcer to Aura Expiry

- Deleted LibGroupInSpecT-1.1.toc, LibStub.lua, and lib.xml files as they are no longer needed.
- Updated localization files (deDE.lua, enUS.lua) to reflect the change from "Buff Ending" to "Aura Expiry".
- Renamed BuffEndingAnnouncer module to AuraExpiry and updated references throughout the codebase.
- Adjusted options and configuration to align with the new module name.
- Updated readme to describe the new Aura Expiry feature instead of Buff Ending Announcer.

Modules/BuffEndingAnnouncer/BuffEndingAnnouncer.lua

@@ -7,7 +7,8 @@ if not HMGT then return end
 
 local L = LibStub("AceLocale-3.0"):GetLocale(ADDON_NAME, true) or {}
 
-local BEA = HMGT:NewModule("BuffEndingAnnouncer")
+local BEA = HMGT:NewModule("AuraExpiry")
+HMGT.AuraExpiry = BEA
 HMGT.BuffEndingAnnouncer = BEA
 
 BEA.runtimeEnabled = false
@@ -426,6 +427,7 @@ function BEA:StopRuntime()
 end
 
 function BEA:OnInitialize()
+    HMGT.AuraExpiry = self
     HMGT.BuffEndingAnnouncer = self
 end