support generics and forward references

[mciszczon]

Closes #131 #160 #250

To close #259

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.30.

Benchmark suite	Current: b20329c	Previous: 1cdc3ef	Ratio
tests/performance/test_from_dict.py::test_casting	140328.6592434538 iter/sec (stddev: 0.0000020240917045147896)	184957.82267943013 iter/sec (stddev: 5.927125345458689e-7)	1.32

This comment was automatically generated by workflow using github-action-benchmark.

[mciszczon]

@avlonder any idea for a better exception message in generics.py:20 (raise DaciteError("Generics error"))?

[avlonder]

@avlonder any idea for a better exception message in generics.py:20 (raise DaciteError("Generics error"))?

What about an f-string "Ambiguous TypeVar {var_name}"?

[mciszczon]

@avlonder any idea for a better exception message in generics.py:20 (raise DaciteError("Generics error"))?

What about an f-string "Ambiguous TypeVar {var_name}"?

I guess that could do! Thanks for all the contributions, I'll release 1.9.0 in the upcoming days :)