Rename eight exercises

[keiravillekode]

Now all practice exercises have names consistent with problem-specifications metadata

https://github.com/exercism/problem-specifications/blob/main/exercises/sum-of-multiples/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/rna-transcription/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/two-fer/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/etl/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/difference-of-squares/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/isbn-verifier/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/game-of-life/metadata.toml

https://github.com/exercism/problem-specifications/blob/main/exercises/pov/metadata.toml

[no important files changed]

[github-actions]

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[BNAndras]

CI is a little flaky on RestApi per #500 so that broken test might end up being okay when we merge this PR.