Add `*OrPtr` unions for all flint types

[lgoettgens]

As suggested in https://github.com/Nemocas/Nemo.jl/pull/1808#discussion_r1658430937

Progress:

• [x] AnticTypes.jl
• [x] FlintTypes.jl
• [x] ArbTypes.jl
• [x] CalciumTypes.jl
• [ ] EmbeddingTypes.jl
• [ ] (GaussianNumberTypes.jl)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 86.35%. Comparing base (03e705a) to head (78bdf2d). Report is 1 commits behind head on master.

Files	Patch %	Lines
src/flint/fmpq.jl	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1813 +/- ## ========================================== + Coverage 85.96% 86.35% +0.38% ========================================== Files 98 98 Lines 36380 37893 +1513 ========================================== + Hits 31274 32722 +1448 - Misses 5106 5171 +65 ```

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