AIP #61 v5: GET /channel/:id/spender/all

[elpiel]

https://github.com/AdExNetwork/aips/issues/61

Related to #391 as this should return all spenders limits

• [x] Route impl #424
• [x] Pagination of response #441

[elpiel]

There are a few tests that still need to be done for the pagination. Please refer to this PR comment:

https://github.com/AdExNetwork/adex-validator-stack-rust/pull/441#pullrequestreview-768975401

[elpiel]

TODOs

• [x] validator_worker::sentry_interface::SentryApi::get_all_spenders to use the paginated responses #451

(from https://github.com/AmbireTech/adex-validator-stack-rust/pull/441#pullrequestreview-768975401):

Make sure to make test that covers:

• 0 records
• less than 1 page of records
• 2 pages of records

This way we can test if queries are correct and returning the expected results

Make sure to write tests for the pagination in Sentry to:

• [x] Check page count #451
• [x] Check ordering & Records #451