Implement preview1 rights handling in the adapters

[rvolosatovs]

Feature

Both standalone preview1 adapter and the "embedded" preview1->preview2 translation layer should implement preview1 rights handling.
Refs #6440 (comment)
Refs #6370

Benefit

Full preview1 functionality without breaking users and/or panicking at runtime

Implementation

Mimic what preview1 already does and implement fd_fdstat_set_rights in both adapters

Alternatives

None really IMO

[pchickey]

We have decided that the rights system is a failed experiment, and I ripped out the support in the legacy code in order to make our test suite consistent across the old and new implementations: #6265

The adapters should just no-op on the calls to set_rights, and the rights flags are only used to determine the read and write oflags in path_open.