wallet: Translate all initErrors in CreateWalletFromFile (MarcoFalke)
util: Make util/error bilingual_str (refactor) (MarcoFalke)
Pull request description:
The translations are going to close in three days (#15940), so I am submitting this as a standalone pull request.
Those changes are part of a bugfix #16661, which includes a test. The first change (the refactor) is required, the second commit is not. I am happy to drop it, if needed.
https://github.com/bitcoin/bitcoin/pull/16745/files
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Backport of Core PR16745