p-adics done right

[joschmitt]

• Cache p-adic and q-adic fields only via the prime number and degree
• Move some code from HeckeMoreStuff to the correct file + some tests
• Introduce user facing constructors padic_field and qadic_field where the precision is a keyword argument
• Add precision keyword arguments to all constructors which take exact input
• Deprecate some functionality like prime_field (should never have been called like that) or lift(::PadicFieldElem) (lifts to ZZ, so one should call lift(ZZ, ...)) + more.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 90.19608% with 20 lines in your changes are missing coverage. Please review.

Project coverage is 85.32%. Comparing base (746d57a) to head (9c5b8e7).

Files	Patch %	Lines
src/flint/qadic.jl	88.70%	14 Missing :warning:
src/Deprecations.jl	0.00%	3 Missing :warning:
src/flint/padic.jl	95.45%	3 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1746 +/- ## ========================================== + Coverage 85.09% 85.32% +0.22% ========================================== Files 95 95 Lines 36917 36903 -14 ========================================== + Hits 31416 31487 +71 + Misses 5501 5416 -85 ```

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[joschmitt]

I think I have now everything we discussed.

[thofma]

Looks good, let's discuss the Hecke breakage tomorrow.

[joschmitt]

This is good to go from my side. It would be good to have a patch release with this, so that I can use it in Hecke.

[thofma]

Very good, thanks