
##### SUMMARY

RDS services can auto-allocate storage. So you can start with the lowest ebs volume and don't care anymore about growing data in der database.  
The boto3 parameter to activate this feature is `MaxAllocatedStorage` (integer) 

>  The upper limit to which Amazon RDS can automatically scale the storage of the DB instance.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
rds_instance


preferred_maintenance_window=dict(aliases=['maintenance_window']),
        processor_features=dict(type='dict'),
        promotion_tier=dict(),
        publicly_accessible=dict(type='bool'),
        restore_time=dict(),
        s3_bucket_name=dict(),
        s3_ingestion_role_arn=dict(),
        s3_prefix=dict(),
        skip_final_snapshot=dict(type='bool', default=False),
        snapshot_identifier=dict(),
        source_db_instance_identifier=dict(),
        source_engine=dict(choices=['mysql']),
        source_engine_version=dict(),
        source_region=dict(),
        storage_encrypted=dict(type='bool'),
        storage_type=dict(choices=['standard', 'gp2', 'io1']),
        tags=dict(type='dict'),
        tde_credential_arn=dict(aliases=['transparent_data_encryption_arn']),
        tde_credential_password=dict(no_log=True, aliases=['transparent_data_encryption_password']),
        timezone=dict(),
        use_latest_restorable_time=dict(type='bool', aliases=['restore_from_latest']),
        vpc_security_group_ids=dict(type='list')
    )
    arg_spec.update(parameter_options)
    required_if = [
        ('engine', 'aurora', ('db_cluster_identifier',)),
        ('engine', 'aurora-mysql', ('db_cluster_identifier',)),
        ('engine', 'aurora-postresql', ('db_cluster_identifier',)),
        ('creation_source', 'snapshot', ('snapshot_identifier', 'engine')),
        ('creation_source', 's3', (