Support discovery of hub+self in HTML <link> tags
The PuSH 0.4 spec says hubs may support <link> tags on HTML pages. It would be great if Superfeedr supported this, to allow more sites to use it. Some web frameworks and hosting environments make it difficult or impossible to set HTTP Link headers, so HTML tags would be the only way to do this.
> In the absence of HTTP [RFC2616] Link headers, subscribers MAY fall back to other methods to discover the hub(s) and the canonical URI of the topic. If the topic is an XML based feed, it MAY use embedded link elements as described in Appendix B of Web Linking [RFC5988]. Similarly, for HTML pages, it MAY use embedded link elements...