perf: Add more moves and optimize (#3845)

* Make slice constructor consistent

* Add more missing std::move for ref steals

* Add missing perfect forwarding for arg_v ctor

* Add missing move in arg_v constructor

* Revert "Add missing move in arg_v constructor"

This reverts commit 126fc7c524ea7a51b54720defd75de3470d69557.

* Add another missing move in cast.h

* Optimize object move ctor

* Don't do useless move

* Make move ctor same as nb

* Make obj move ctor same as nb

* Revert changes which break MSVC