feat: add index for member api (CM-764) (#3588)

Author: ulemons

backend/src/database/migrations/U1762789440__optimize_member_api.sql

@@ -0,0 +1,12 @@
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_msa_segment_activitycount_desc_member
+ON public."memberSegmentsAgg" ("segmentId", "activityCount" DESC, "memberId");
+
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_members_displayname_trgm
+ON public."members"
+USING gin (LOWER("displayName") gin_trgm_ops);
+
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_memberidentities_email_verified_trgm
+ON public."memberIdentities"
+USING gin (LOWER("value") gin_trgm_ops)
+WHERE verified = true
+  AND type = 'email';