add Bluesky icon, remove Twitter icon in Footer - Global Area with partial current Vocabulary sync

[possumbilities]

Description

• syncs changes from: Fix URL syntax in @font-face declarations for improved browser compatability vocabulary#102
• syncs changes from: Ensure ../svg/ paths are simplified and consistent in vocabulary.css and library-vars.css vocabulary#258
• syncs changes from: Fix CSS Class typos and Variable Name. vocabulary#263
• Fixes [Functionality] sync Footer - Global Area changes from Vocabulary #81

This is an incomplete sync of current Vocabulary, changes regarding vocabulary.css and Contextual markup outside the scope of the social icon change here are not yet included. Additional changes to bring Vocabulary to full current state within vocabulary-theme will be included in a future PR.

Checklist

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