Make sub dir per language

[sverhoeven]

Fixes #23

Also made python/src/remotebmi/server/openapi.yaml a copy instead of a symlink

Fixes #6

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.19%. Comparing base (b0aa7e7) to head (ab0a51c). Report is 5 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #26 +/- ## ========================================== + Coverage 87.62% 89.19% +1.56% ========================================== Files 42 44 +2 Lines 1778 2147 +369 ========================================== + Hits 1558 1915 +357 - Misses 220 232 +12 ``` | [Components](https://app.codecov.io/gh/eWaterCycle/remotebmi/pull/26/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eWaterCycle) | Coverage Δ | | |---|---|---| | [Python](https://app.codecov.io/gh/eWaterCycle/remotebmi/pull/26/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eWaterCycle) | `∅ <ø> (∅)` | | | [Julia](https://app.codecov.io/gh/eWaterCycle/remotebmi/pull/26/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eWaterCycle) | `87.62% <ø> (∅)` | | | [R](https://app.codecov.io/gh/eWaterCycle/remotebmi/pull/26/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=eWaterCycle) | `96.74% <ø> (∅)` | |