If the new implementation works reliably (the data in both tables looks the same), we should remove the existing code that picks up banner impression data from the IMAP inbox and change the analysis code to use the new database tables.
**Implementation details**
// TODO table of needed SQL changes
Remove
* `application/Commands/FetchImpressionsCommand.php`
* `src/DataAccess/DoctrineEntity/BackendImpression.php` - this is now `BannerImpression`
* `src/DataAccess/DoctrineEntity/BackendBanner.php` - this is now `BannerTracking`
* `Banner::getBannerMapping()` and its private method from `application/model/Banner.php`
* `Impression::storeImpression` and `Impression::extractTimestamp` from `application/model/Impressions.php`
Adapt in SQL queries:
* `Impression::getImpressionsPerHour` and `Impression::extractTimestamp` from `application/model/Impressions.php`
* `application/model/Analysis.php` search for table and column names and replace them
* `BannerImpressionRepository::getBannerImpressions` - adapt SQL and move method to `BannerImpressions\ImpressionRepository`, changing the dependencies
* `ToolsHelpers::getImpressionCount` - ask Kai if the script using the `ToolsHelper` method - `campaignExport.php` is still needed and what purpose it serves
* Discuss deletion of `DatabaseInstallationTest` - dubious value of testing the db setup for the test environment.
* `test/Data/files/database/banners.sql` needed for the analysis test, replace with a dump from the new tables