Configuration to map dimension, measure, or attribute values to use a prefered namespace #42
Description
It should be possible to configure dimension, attribute, or measure values based on the concept that's defined in the config file to any namespace. For example, ECB uses the TIME_FORMAT concept for an attribute (which is a isTimeFormat) where the values in the dataset for this attribute is a member of CL_TIME_FORMAT in http://sdmx.org/wp-content/uploads/2009/01/02_sdmx_cog_annex_2_cl_2009.pdf. So, in this case, use the appropriate concept from sdmx-code:timeFormat.
Relates to issue #34 but this is for values instead of properties.