Move all default attributes to default attributes file

Except the ones related to the zookeeper recipe.
Add nicer failure message for have_configured matcher
Update attributes related to configuration of Kafka broker

There were a whole slew of new attributes introduced in the final release of v0.8.0, as well as a few removed (metrics related).
Also handles 'map' based attributes, i.e. per topic specific attributes.

Not too happy about some of the attribute naming, so might change that in a near future, but other than that this should be good to go.
Update specs for configuration options

Managed to squash a few typo bugs as well. Still need to take care of 'map' based options, i.e. hashes transposed to CSV strings.
Update test case descriptions for configure spec
Add actual specs for previously pending examples
Remove unused `data_dir` attribute
Update documentation (README, comments)

[ci skip]
Refactor Kafka configuration template

* Use partials.
* Guard against configuration nil values.
* Refactor map/hash based options.
Suppress new lines when rendering partials
Merge branch 'update-broker-configuration'
Update .ruby-gemset to `kafka-cookbook`
Update chefspec to v3.1.2 and test-kitchen to v1.1.1
Update .gitignore
Add ChefSpec::Coverage.report! to spec_helper
Update specs to increase coverage
Refactor default spec
Further cleanup of default spec
Remove unnecessary integration test case
Bump recommended version of java cookbook