feat(data): Add vertical inequality indicators

Added from our own project notes on vertical inequality indicator
families. Should be ultimately checked in a pass for usability
once the quantitative analysis is further along.

notes.md

@@ -574,6 +574,9 @@ Tagging:
 - income:
     - Palma ratio [@DFI2023]
     - Gini coefficient [@DFI2023]
+    - Log deviation [our quant indicators]
+    - Theil [our quant indicators]
+    - Atkinson [our quant indicators]
 - class @Kalasa2021
 - fertility @Kalasa2021
 - NOT identified by previous reviews, need to find sources:

scoping_review.qmd

@@ -453,6 +453,9 @@ inequality_terms_cluster = {
         "income",
         "Palma ratio [@DFI2023]",
         "Gini coefficient [@DFI2023]",
+        "Log deviation",
+        "Theil",
+        "Atkinson",
         "class [@Kalasa2021]",
         "fertility [@Kalasa2021]",
         "bottom percentile",