Feature: Add YAML support for 'page' type files (not just for 'datafile' type)

[elingerojo]

It will be nice to have single markup files that include its own data objects like frontmatter but letting more complex objects by YAML syntax.

At present, for complex objects you need to use two files, one for the page and one for the data.

A simple approach is to enable html-frontmatter to accept YAML.

1. Developers get the option to centralize or distribute their data at convenience.
2. Developers could have markup and context in one autonomous file to move around.

There is a PR ready at html-frontmatter repository

PS:
I am sorry for posting the same issue on two repositories but now I understand that I should have started here not in html-frontmatter (... and after discussion, if needed, move the discussion there).

[elingerojo]

Closed because html-frontmatter deals with Github issues that YAML can not (meaning, this issue was not such a good idea after all 😀 )