Support extending the refinement types with more annotations

[espetro]

Currently, refinement type annotations do not support additional annotations, e.g. annotating a non-empty list with a ValueRange:

from refined import NonEmpty
from some_module import ValueRange
from typing import List

not_valid = NonEmpty[List[str], ValueRange(0, 10)]
not_valid_neither = NonEmpty[List[str]](extra_annotations=[ValueRange(0, 10)])

However, as explained in the PEP 593, Nested Annotated types are flattened, with metadata ordered starting with the innermost annotation:

from refined import NonEmpty
from some_module import ValueRange
from typing import List

valid = Annotated[NonEmpty[List[str]], ValueRange(0, 10)]

So it should be also OK if we do not support this.