Do not store standard types statically but keep them on the Schema instead

[ruudk]

When working with 2 schemas that have different standard types this becomes problematic.

For example, I have a schema that uses a custom ID type, but the other wants to use the default.

I can imagine this is not easily possible currently because of the way types are resolvable without a Schema (#1149).

[spawnia]

This is a large breaking change, so I will plan this for v16.

Until then keep in mind that while static, the standard types can be manipulated dynamically. Unless you need to serve both schemas in the same execution context, you can work around this issue.

[ruudk]

See issue #1424 for a possible solution