Currently we only support adding an endpoint suffix for azure repositories. This is not enough when a custom Azure DNS  zone is used since the URI that's created using an endpoint suffix is incorrect.
```java
primaryUri = new URI(protocol + "://" + accountName + "." + service + "." + endpointSuffix);
``` 

We should add the ability to provide a custom endpoint to cover this situations.
modules/repository-azure/src/test/java/org/elasticsearch/repositories/azure/AzureStorageServiceTests.java
endpoint = "core.windows.net";
        } else {
            endpoint = "ignored;BlobEndpoint=https://myaccount1.blob.core.windows.net;"
                + "BlobSecondaryEndpoint=https://myaccount1-secondary.blob.core.windows.net";
        }
        final Settings settings = Settings.builder()
            .setSecureSettings(buildSecureSettings())
            .put("azure.client.azure1.endpoint_suffix", endpoint)
            .build();
        try (AzureRepositoryPlugin plugin = pluginWithSettingsValidation(settings)) {
            final AzureStorageService azureStorageService = plugin.azureStoreService.get();
            AzureStorageSettings azureStorageSettings = azureStorageService.storageSettings.get("azure1");
            RequestRetryOptions retryOptions = azureStorageService.getRetryOptions(
                LocationMode.PRIMARY_THEN_SECONDARY,
                azureStorageSettings
            );
            assertThat(retryOptions.getSecondaryHost(), equalTo("https://myaccount1-secondary.blob.core.windows.net"));
        }
    }
    public void testRetryConfigurationForPrimaryFallbackLocationMode1() throws Exception {
        testRetryConfigurationForPrimaryFallbackLocationModeImpl(true);
    }
    public void testRetryConfigurationForPrimaryFallbackLocationMode2() throws Exception {
        testRetryConfigurationForPrimaryFallbackLocationModeImpl(false);
    }
    private void testRetryConfigurationForPrimaryFallbackLocationModeImpl(boolean endpointSetting) throws Exception {
        final String endpoint;
        if (endpointSetting) {
            endpoint = "core.windows.net";
        } else {