Add Instance History indexing to checksum & uuid fields

[KipSigei]

Changes / Features implemented

• Create indexing for uuid and checksum columns on the Instance History table

Steps taken to verify this change does what is intended

• Applied migrations and ran EXPLAIN ANALYZE on a query against the logger_instancehistory table

Side effects of implementing this change

• Optimizes ORDER BY queries against the Instance History table

db=> EXPLAIN ANALYZE SELECT "logger_instancehistory"."id", "logger_instancehistory"."xform_instance_id" FROM "logger_instancehistory" INNER JOIN "logger_instance" ON ("logger_instancehistory"."xform_instance_id" = "logger_instance"."id") WHERE ("logger_instancehistory"."uuid" = 'random-uuid' AND "logger_instance"."deleted_at" IS NULL AND "logger_instance"."xform_id" = <xform_id>) ORDER BY "logger_instancehistory"."id" ASC LIMIT 1;
                                                                                QUERY PLAN                                                                                
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=15.97..15.98 rows=1 width=8) (actual time=0.020..0.020 rows=0 loops=1)
   ->  Sort  (cost=15.97..15.98 rows=1 width=8) (actual time=0.019..0.020 rows=0 loops=1)
         Sort Key: logger_instancehistory.id
         Sort Method: quicksort  Memory: 25kB
         ->  Nested Loop  (cost=1.12..15.96 rows=1 width=8) (actual time=0.016..0.016 rows=0 loops=1)
               ->  Index Scan using logger_instancehistory_uuid_idx on logger_instancehistory  (cost=0.56..5.61 rows=4 width=8) (actual time=0.015..0.015 rows=0 loops=1)
                     Index Cond: ((uuid)::text = '<random-uuid>'::text)
               ->  Index Scan using logger_instance_id_xform_id_index on logger_instance  (cost=0.57..2.59 rows=1 width=4) (never executed)
                     Index Cond: ((xform_id = <xform-id>) AND (id = logger_instancehistory.xform_instance_id))
                     Filter: (deleted_at IS NULL)
 Planning Time: 0.276 ms
 Execution Time: 0.039 ms
(12 rows)

Before submitting this PR for review, please make sure you have:

• Included tests
• Updated documentation

Closes #