NIAD-3453: Refactor StorageService to correctly use DI/IOC

[MartinWheelerMT]

What

• Delete StorageServiceFactory.java and StorageServiceFactoryConfig.java as unnecessary and confusing steps in the DI process.
• Introduce StorageServiceConfig to conditionally create the required service.
• Refactor AzureStorageService to now correctly inject the StorageServiceClient from the IOC container.
• Add Integration Test sfor AzureStorageService.
• Add testcontainers to build.gradle to enable use of Azurite.

Why

DI was incorrectly set up and abstracted multiple times, causing the storage service to be manually created rather than correctly injected. This was refactored so that the bean is now correctly using IOC.
Since its creation the AzureStorageService class has not had any test coverage, and it's in our best interest to add this.

Type of change

• Internal change (non-breaking change with no effect on the functionality affecting end users)

Checklist:

• I have performed a self-review of my code
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes

[github-actions]

Images built and published to ECR using a Build Id of PR-1031-4970435

[github-actions]

• Surviving mutants in this change: 2
• Killed mutants in this change: 4

class	surviving	killed
🧟uk.nhs.adaptors.pss.translator.storage.StorageServiceConfig	2	4

See https://pitest.org

• Arcmutate licence valid until 2028-03-02 (yyyy/mm/dd) (non-commercial use only)
• Project uses Spring, but the Arcmutate Spring plugin is not present.

[chiaramapellimt]

LGTM