HV-905 Providing a global config for auto unwrapping

An early attempt. Any thoughts on the direction?
Rightly, @hferentschik brought up the potential ambiguity around `@NotNull`, e.g. whether to unwrap in this case or not. And indeed that needs to be addressed.

So I tried to list up what possibilities there actually are and what the validation behavior IMO should be:

no. | Validator exists for wrapper | Validator exists for wrapped | Unwrapper exists | Example | Desirable result
--- | --- | --- | --- | --- | ---
1 | - | - | - | - | Declaration error
2 | - | - | x | @Future Optional&lt;Integer&gt; myInt; | Declaration error
3 | - | x | - | @Min(3) Holder&lt;Integer&gt; myHolder; | Declaration error
4 | - | x | x | @Min(3) Optional&lt;Integer&gt; myInt; Optional<@Email String>; | Validate wrapped
5 | x | - | - | @ValidHolder Holder myHolder; | Validate wrapper
6 | x | - | x | @ValidHolder Holder myHolder; | Validate wrapper
7 | x | x | - | @NotNull Holder myHolder; | Validate wrapper
8 | x | x | x | @NotNull IntegerProperty myInt; | Validate wrapper; Use explicit `@UnwrapValidatedValue` to validate wrapped

My thinking now is that we could get rid of the global switch and enable auto-unwrap out of the box, strictly applying these rules. Which is basically "unwrap if we sensibly can, otherwise don't unwrap". An explicit `@UnwrapValidatedValue` would only be required to resolve the ambiguity in case 8.

This simplifies the most cases, while getting rid of ambiguities and the complexity of a global switch.

Note that the matrix looks more complicated than I think it is in reality. 95% of cases will be like case 4) where we apply the unwrapping as users will intuitively expect it. The only stumbling stone may be case 8) but I expect `@(Not)Null` to be the only case where it actually is a problem, as otherwise an overlap of validators between wrapper types and wrapped types is very unlikely. Validating the wrapper and optionally enforcing unwrapping via `@UVV` seems like the right way in this case to me.

Would that work for you guys?