Remove the 'if codelist not specified assume X'

In order to ‘standardise the standard’ we should remove all the areas where when a codelist is not specified (e.g. sector vocabulary), then one of the codelists is set as the default (although not in any way a machine could follow). This would make the standard less complex e.g. easier for users who would not need to maintain their own lists of where these rules apply. These typically also reinforce the idea of IATI as a DAC centric institution which is not helpful.

A very second best solution would be a way for IATI data consuming systems to track these ‘defaults’.