Create a Jekyll data file with topic information and use it for topic links

[dagoss]

Jekyll can work with JSON, YAML, and CSV files natively. Most configuration of Jekyll is done with yaml, so that's probably the preferred tool here.

The plugin should generate a data file of my-map.ditamap named my-map.yml with a structure like this:

uniqe-id-for-topic1:
  - title: "The Title of the Topic 1"
  - url: "relative/path/to/topic1/"
uniqe-id-for-topic2:
  - title: "The Title of the Topic 2"
  - url: "relative/path/to/topic2/"

Instead of using hrefs to topics in the output, mustache templates should be used instead. So a link to one of the topics above would appear as:

<a href="{{ site.data.my-map.unique-id-for-topic1.url }}">site.data.my-map.unique-id-for-topic1.title</a>

This would allow URLs to be further processed by Jekyll before pushing content. It might also be useful in the future to have more data about topics in the data file (such as keywords, shortdesc, and other metadata).