🚚 Move string coordinates simplification

[je-cook]

Description

This moves some code from eudemo to bluemira around coordinates. I did this while sorting out #3386 but realised it became a bit big so split it out. Should go in before #3386

Interface Changes

Checklist

I confirm that I have completed the following checks:

• [ ] Tests run locally and pass pytest tests --reactor
• [ ] Code quality checks run locally and pass pre-commit run --from-ref develop --to-ref HEAD
• [ ] Documentation built locally and checked sphinx-build -W documentation/source documentation/build

[sonarcloud[bot]]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 97.36842% with 1 line in your changes missing coverage. Please review.

Project coverage is 74.51%. Comparing base (859d57b) to head (32e6bdb).

Files	Patch %	Lines
bluemira/geometry/coordinates.py	97.36%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #3393 +/- ## =========================================== + Coverage 74.48% 74.51% +0.03% =========================================== Files 230 230 Lines 26776 26813 +37 =========================================== + Hits 19943 19979 +36 - Misses 6833 6834 +1 ```

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[github-actions[bot]]

⚠️ Warning Report

Found 0 new warnings, 0 fixed warnings. 🎉

All warnings (5)

#### On runtest - `/home/runner/miniconda3/envs/bluemira/lib/python3.10/site-packages/ffcx/element_interface.py:23: DeprecationWarning: Use of elements created by UFL is deprecated. You should create elements directly using Basix.` - `/home/runner/miniconda3/envs/bluemira/lib/python3.10/site-packages/ffcx/element_interface.py:26: DeprecationWarning: Converting elements created in UFL to Basix elements is deprecated. You should create the elements directly using basix.ufl.element instead` - `/home/runner/miniconda3/envs/bluemira/lib/python3.10/site-packages/ufl/core/expr.py:275: DeprecationWarning: Expr.ufl_domain() is deprecated, please use extract_unique_domain(expr) instead.` - `/home/runner/miniconda3/envs/bluemira/lib/python3.10/site-packages/basix/ufl.py:1909: DeprecationWarning: Converting elements created in UFL to Basix elements is deprecated. You should create the elements directly using basix.ufl.element instead` #### On collect - `/home/runner/miniconda3/envs/bluemira/lib/python3.10/site-packages/ufl/core/ufl_type.py:56: DeprecationWarning: attach_operators_from_hash_data deprecated, please use UFLObject instead.`