Prevent illegal bindings of unique ptrs

 Add flag to prevent all binding of unique ptrs

 Unique ptrs need more nuanced handling, but for now this will work
3 jobs for !180 with bug/fixup-unique-constructor in 13 minutes and 51 seconds (queued for 1 second)
merge request
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python3 Build
   Uploaded: /builds/autopybind11/autopybind11/build/Testing/20210608-1813/Test.xml
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Errors while running CTest
Output from these tests are in: /builds/autopybind11/autopybind11/build/Testing/Temporary/LastTest.log
Use "--rerun-failed --output-on-failure" to re-run the failed cases verbosely.
Cleaning up file based variables
ERROR: Job failed: exit code 1