Repose | Rename "respondent id" > "pseudonym" throughout app

The term "respondent ID" is deprecated and should be replaced by "pseudonym" all throughout the app. It may still be used to explain the term "pseudonym" in the docstrings, though.

The German "Teilnamecode" is also to be replaced since the German study information also uses the term "Pseudonym".

changed milestone to %REPOSE study

added Doing Refactoring Variant: Repose labels

assigned to @noel.simmel

created branch 565-repose-rename-respondent-id-pseudonym-throughout-app to address this issue

changed the description

mentioned in commit c7e24695

closed