Extend API v1 with endpoints used by new UI

[vbaranov]

Motivation

There are some Api v1 endpoints which are not under /api/v1 path, b ut they are used in new UI:

• /graphql
• /transactions-csv
• /token-transfers-csv
• /internal-transactions-csv
• /logs-csv

In order to simplify devops configuration of proxy between back and front, it is suggested to move them under /api/v1 endpoint

Changelog

• /graphql -> /api/v1/graphql
• /transactions-csv -> /api/v1//transactions-csv
• /token-transfers-csv -> /api/v1/token-transfers-csv
• /internal-transactions-csv -> /api/v1/internal-transactions-csv
• /logs-csv -> /api/v1/logs-csv

Checklist for your Pull Request (PR)

• I added an entry to CHANGELOG.md with this PR
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
• I checked whether I should update the docs and did so by submitting a PR to https://github.com/blockscout/docs
• If I added/changed/removed ENV var, I submitted a PR to https://github.com/blockscout/docs to update the list of env vars at https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables.md and I updated the version to master in the Version column. Changes will be reflected in this table: https://docs.blockscout.com/for-developers/information-and-settings/env-variables.
• If I add new indices into DB, I checked, that they are not redundant with PGHero or other tools