Adds some 1.17 features for the future and overhauls the look of iron weapons to match New Default+ v1.37

Ver. 2.1 - 1/1/2021 - "1.17 Support & Iron Update"
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Additions:
+Readded emissive textures for ancient debris (top & side) {Optifine Required} {Java 1.17+, Java 1.16.2-1.16.4, & Java 1.15-1.16.1 packs only}
+Added emissive textures for copper ore (normal & 1-3) {Optifine Required} {Java 1.17+ pack only}
+Added emissive textures for powder snow {Optifine Required} {Java 1.17+ pack only}

Changes & Fixes:
~Changed creator_links.txt
~Changed all iron tool textures
~Changed nausea texture {Java 1.17+, Java 1.16.2-1.16.4, & Java 1.15-1.16.1 packs only}