Code list Sampler - change SelfSamp to Fisher

[KirstenBirchHaakansson]

WGCATCH recommends that the code SelfSamp in the code list sampler, https://vocab.ices.dk/?ref=1639, is changed to Fisher, since more terms than self-sampling are being used to describe sampling schemes where fishers take actively part in the sampling, e.g., co-sampling

[HenrikK-N]

The code 'self-sampling' will be update to 'Fisher'. It depend on RMG and if any countries have uploaded data, whether it will be changed very soon or from next year.