Merge pull request opencv#19078 from zihaomu:dasiamrpn_tracker_c_plus_plus

Add DaSiamRPN tracker sample of c++ version

* add sample dasiamrpn_tracker of c++ version.

* samples(dasiamrpn_tracker.cpp): apply clang-format

- exclude "keys" variable

* samples(dasiamrpn_tracker.cpp): coding style and UX fixes

Author: zihaomu