External seed for pseudo-random number generator

[Flogex]

I'm using faker-cxx to generate random data for databases. To test the library and make the generation more deterministic in general, it would be great to be able to provide an explicit seed for the pseudo-random number generator.
Currently, the seed is set with std::random_device:

faker-cxx/include/faker-cxx/helper.h

Lines 41 to 42 in 1f76b3d

	std::random_device rd;
	std::mt19937 gen(rd());

faker-cxx/include/faker-cxx/number.h

Line 37 in 1f76b3d

static std::mt19937 pseudoRandomGenerator{std::random_device{}()};

Are you interested in adding this functionality? I'm happy to implement it.

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Implementation-wise, I'm considering two alternatives. Let me know if I'm missing something—I'm still new to the code. :)

1. Providing a seed as parameter of the existing API functions. For example: faker::internet::email(seed=42). The disadvantage is that this would change the signature of all API functions and add an optional parameter. The advantage is that the rest of the code can stay the same (e.g., how RNGs are instantiated).
2. Using a single thread_local std::mt19937 instead of a static local for every function that needs a random engine, and adding a function to change its seed. This doesn't change the signature of any existing functions.

[cieslarmichal]

Hello, very good idea, let's implement it :)
Second solution seems to be better :)
I will assign you to this issue