Integrate Discourse for Commenting

[dternyak]

Discourse, which powers the Zcash discussion forum, offers a full-featured interface and serves as a hub for communication across the Zcash community.

@tromer recently brought it to my attention that Discourse supports a Javascript + IFRAME based integration that allows external sites to embed threads into their site. See https://meta.discourse.org/t/embedding-discourse-comments-via-javascript/31963.

In addition to enhancing the comment system, Discourse integration would serve as a sort of relay between ZF Grants and the Discourse forum. ZF Grants related discussion would automatically have threads spawned on the forum. Given that the forum experiences a significant amount of community discussion, this integration could serve to facilitate greater discussion and community interest on proposals being issued on ZF Grants.