[FEA]: `cuda::std::join_view`

[brycelelbach]

Is this a duplicate?

• [ ] I confirmed there appear to be no duplicate issues for this request and that I agree to the Code of Conduct

Area

Thrust

Is your feature request related to a problem? Please describe.

I'd like to use it in #6470

Describe the solution you'd like

Provide cuda::std::join_view backported to C++17.

Describe alternatives you've considered

No response

Additional context

No response

[miscco]

I have this implemented already but I need people to actually review the nontrivial PR