Maintenance: simplify `hive` and `i2b2_mapping` logic

[Vincent-Maladiere]

Description

Checklist

• [ ] If this PR is a bug fix, the bug is documented in the test suite.
• [ ] Changes were documented in the changelog (pending section).
• [ ] If necessary, changes were made to the documentation (eg new pipeline).

[codecov-commenter]

Codecov Report

:exclamation: No coverage uploaded for pull request base (i2b2@53f6e76). Click here to learn what that means. Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## i2b2 #24 +/- ## ======================================= Coverage ? 92.17% ======================================= Files ? 66 Lines ? 2121 Branches ? 0 ======================================= Hits ? 1955 Misses ? 166 Partials ? 0 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aphp). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aphp)

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