Load template from the search path provided in the recipe

Rather than using a complete path, the template path is now relative
to any of the template path set in the Recipe.
First commit of the #cake gradle plugin

The plugin provides a "bake" task that will build the documentation
present under:

/src/documentation/markdown
  where all the markdown sources should sit

/src/documentation/templates
  where the document template must be named "template.html" atm

/src/documentation/resources
  where all other web resources must be (js, css, images)

It doesn't allow to override these paths for now.
First version of the documentation

Although under the same folder, the documentation is not a subproject
because it depends on the gradle plugin.

To "bake" the documentation, first, other projects must be published:
cake> ./gradlew publish

For the time being, publication is local, thus, the documentation
can use the local maven repo to source the plugin.

Then, to build the documentation:
cake/cake-documentation> ./gradlew bake