Add Tier 1 Etude spells and update etude.lua

Added T1 Etudes based on BG wiki.

Tier 1 Etudes
Combined Skill Range Bonus
≤181 Skill +3 Attribute
182~235 Skill +4 Attribute
236~288 Skill +5 Attribute
289~342 Skill +6 Attribute
343~396 Skill +7 Attribute
397~449 Skill +8 Attribute
≥450 Skill +9 Attribute