Mark which core HST Spring Ids are SPI and which ones are API

In future versions, it is likely that we will drop quite some more Spring Ids from the HST Core Spring Component Manager. In version 13.0.0 and before, quite some Spring Ids are possible to override or to use in a custom Spring bean, however, they were never intended to be overridden or to be used. Overriding (SPI) or using (API) to HST Core Component Manager Spring Ids is not supported unless explicitly mentioned as a Spring API id. At this moment, we have the following Spring SPI/API ids which we treat as SPI/API. To clarify, the SPI ids are expected to be overridden if needed, the API ids should never be overridden but can be used / referenced.