add query types to generate_storage_alias

[apopiak]

This PR adds support for specifying the QueryKind to the generate_storage_alias macro.
It can be specified as the last type parameter like so:

generate_storage_alias!(Prefix, ValueName<T: Config> => Value<T::Balance, ValueQuery>);

⚠️ Breaking Change:

Changes the default QueryKind for Value storage aliases with a generic type (like in the example above) to the default of the underlying type, which is OptionQuery (the macro used to hard-code ValueQuery before).

[apopiak]

What's the unleash check about?

[apopiak]

bot merge

[ghost]

Trying merge.

[kianenigma]

What's the unleash check about?

should be ignored for now.