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/main/java/org/elasticsearch/repositories/azure/AzureStorageSettings.java
() -> ACCOUNT_SETTING
    );
    
    public static final AffixSetting<String> PROXY_HOST_SETTING = Setting.affixKeySetting(
        AZURE_CLIENT_PREFIX_KEY,
        "proxy.host",
        (key) -> Setting.simpleString(key, Property.NodeScope),
        () -> ACCOUNT_SETTING,
        () -> PROXY_TYPE_SETTING
    );
    
    public static final Setting<Integer> PROXY_PORT_SETTING = Setting.affixKeySetting(
        AZURE_CLIENT_PREFIX_KEY,
        "proxy.port",
        (key) -> Setting.intSetting(key, 0, 0, 65535, Setting.Property.NodeScope),
        () -> ACCOUNT_SETTING,
        () -> PROXY_TYPE_SETTING,
        () -> PROXY_HOST_SETTING
    );
    private final String account;
    @Nullable
    private final String sasToken;
    private final String connectString;
    private final String endpointSuffix;
    private final TimeValue timeout;
    private final int maxRetries;
    private final Proxy proxy;
    private AzureStorageSettings(
        String account,
        String key,