add log index to transaction view

[ayrat555]

if a transaction has a big number of logs it's not apparent which page of logs is requested. Also, log index is used for logs pagination

Changelog

• add log index to transaction view

[coveralls]

Pull Request Test Coverage Report for Build 6730a2eb-fa07-42bf-93ad-fec3efcc5b77

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 6 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.1%) to 81.175%

---

Files with Coverage Reduction	New Missed Lines	%
apps/indexer/lib/indexer/fetcher/token.ex	1	78.57%
apps/indexer/lib/indexer/fetcher/token_balance.ex	2	87.1%
apps/indexer/lib/indexer/block/fetcher.ex	3	87.84%

Totals
Change from base Build 17f65b6f-b33a-4dad-b400-ad1d5d8fd47d:	-0.1%
Covered Lines:	4713
Relevant Lines:	5806

---

💛 - Coveralls

[zachdaniel]

I realized after approving that this change should also be reflected in the rpc documentation in etherscan.ex