Resolve "Use DOIs as PIDs"

Closes #290

added scope::Backend status::Doing + 1 deleted label

requested review from @mweise

assigned to @grantnert48

added 2 commits

• f714e7e8 - Adjusted old identifier export tests and added new ones checking for DOIs
• ea5cfdb6 - Changed tests to not alter obects in BaseTest, which can produce side effects

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approved this merge request

mentioned in commit d52cf452

merged