Add API for restoring Pseudorandom and PcgRandom state

[sfence]

Add compact, short information about your PR for easier understanding:

• Allow PsedoRandom and PcgRandom pseudorandom number generators to be restored in a known state
• It resolves lua api: PseudoRandom: peek at current rng state to allow save/restore #14107

To do

This PR is Ready for Review.

How to test

Run /unittests command from devtest game and minetest --run-unittests command from system.

[appgurueu]

Looks good apart from this. (Small note: I don't really care what happens to PseudoRandom as it is strictly inferior to PcgRandom, see #14180).

[sfence]

@appgurueu @sfan5 Should be resolved now.

[appgurueu]

Otherwise the code looks fine. I'm not happy with how PseudoRandom uses int rather than a fixed-size type (which might be related to bugs like #14237), but that is out of scope for this PR to fix.

[appgurueu]

Tested, works. Thanks for the PR!

[sfence]

Rebased, conflicts solved.

Failure for clang_14 looks to be related to check failure:

 (server) [PASS] test_node_metadata - 0ms
(server) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
(server) Unit Test Results: PASSED
(server)     0 / 35 failed tests.
(server)     Testing took 12450ms total.
(server) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Waiting for done timed out
Error: Process completed with exit code 1.

[sfan5]

Looks good other than that