Fix aggregations use statements and return values

[simpleadm]

Description

Several classes have wrong use statements for AggregationInterface (Magento\Framework\Search\AggregationInterface instead of Magento\Framework\Api\Search\AggregationInterface).
Also I have found that some setAggregations methods doesn't return value (incompatible with interface annotation).

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @simpleadm. Thank you for your contribution.
Changes from your Pull Request will be available with the upcoming 2.3.0 release.