feat(themes): added ayu mirage, light, and dark themes (zellij-org#3567)

Co-authored-by: Evan Lauer <evanlauer@u.boisestate.edu>

zellij-utils/assets/themes/ayu.kdl

@@ -0,0 +1,46 @@
+// Author: Evan Lauer <evthestrike@gmail.com>
+// Based on the AYU theme colors from https://github.com/dempfi/ayu
+
+themes {
+    ayu_mirage {
+        fg "#CCCAC2"
+        bg "#1F2430"
+        black "#1A1F29"
+        red "#F28779"
+        green "#D5FF80"
+        yellow "#FFCC77"
+        blue "#73D0FF"
+        magenta "#DFBFFF"
+        cyan "#444B55"
+        white "#C7C7C7"
+        orange "#FFAD66"
+	}
+
+	ayu_light {
+		fg "#5C6166"
+		bg "#FAFAFA"
+		black "#E7EAED"
+		red "#F07171"
+		green "#86B300"
+		yellow "#FFAA33"
+		blue "#399EE6"
+		magenta "#A37ACC"
+		cyan "#478ACC"
+		white "#FCFCFC"
+		orange "#FA8D3E"
+	}
+
+	ayu_dark {
+		fg "#BFBDB6"
+		bg "#0F1419" 
+		black "#131721"
+		red "#F07178"
+		green "#AAD94C"
+		yellow "#E6B450"
+		blue "#59C2FF"
+		magenta "#D2A6FF"
+		cyan "#73B8FF"
+		white "#CCCAC2"
+		orange "#FF8F40"
+	}
+}