Tailor accessibility metric for CKAN metadata

Just changed the compute method of the accessibility metric to process
the different CKAN metadata record fields which contain a descriptive
test. For now this will be the general notes field and each description
field of the resources.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Integrate accessibility metric into the interface

For the accessibility metric is does not make much sense to use a
circular meter to visualize it. For now I will only display the
result. For that I had to extend the CoffeeScript code.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>