Add indexes

[DOBEN]

Purpose

Related to: Concordium/concordium-wallet-proxy#174

Optimized queries of the form:

SELECT "ati"."id", "ati"."account", "ati"."summary", "summaries"."id", "summaries"."block", "summaries"."timestamp", "summaries"."height", "summaries"."summary"
FROM "ati" INNER JOIN "summaries" ON "ati"."summary" = "summaries"."id"
WHERE ("ati"."account" = decode('12717900048886D2FE34C5042C3C127B6C11E321A4C1A95B572D3D12508EDE0B', 'hex')) AND ("summaries"."height" >= 43619225)
ORDER BY "ati"."id" ASC

When the range of blocks is small the indexes are used. For very large ranges, the query plan still uses a Parallel Seq Scan with an account that has a lot of summaries.

Changes

• Add indexes to optimize fetching summaries for a specific account and filtering entries by block height or timestamp.
• Add indexe to optimize fetching summaries for a specific account and efficient ordering by row id.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.

CLA acceptance

_Remove if not applicable.

By submitting the contribution I accept the terms and conditions of the
Contributor License Agreement v1.0

• link: https://developers.concordium.com/CLAs/Contributor-License-Agreement-v1.0.pdf

• I accept the above linked CLA.