feat: add booster eligibility role and logging functionality

- Added BOOSTER_ELIGIBILITY_ROLE_ID and LOG_LEVEL to .env.example and README.md
- Updated GitHub Actions workflow to include new environment variables
- Enhanced configuration loading to support booster eligibility role
- Implemented role checking logic in bot handlers and guild member updates
- Introduced logging using Winston for better traceability of actions
- Created tests for guild member update handling to ensure correct role removal
- Refactored DiscordRoleRepository to simplify role position resolution

.env.example

@@ -3,3 +3,5 @@ DISCORD_CLIENT_ID=
 DISCORD_GUILD_ID=
 DATABASE_URL=postgresql://booster_role:booster_role@localhost:5432/booster_role
 BOOSTER_ROLE_ANCHOR_ROLE_ID=
+BOOSTER_ELIGIBILITY_ROLE_ID=1206431347925852162
+LOG_LEVEL=info