Merge pull request #20271 from TolyaTalamanov:at/extend-python-bindings

G-API: Extend python bindings

* Extend G-API bindings

* Wrap timestamp, seqNo, seq_id
* Wrap copy
* Wrap parseSSD, parseYolo

* Rewrap cv.gapi.networks

* Add test for metabackend in pytnon

* Remove int64 pyopencv_to

modules/gapi/src/api/ginfer.cpp

@@ -15,6 +15,10 @@ cv::gapi::GNetPackage::GNetPackage(std::initializer_list<GNetParam> ii)
     : networks(ii) {
 }
 
+cv::gapi::GNetPackage::GNetPackage(std::vector<GNetParam> nets)
+    : networks(nets) {
+}
+
 std::vector<cv::gapi::GBackend> cv::gapi::GNetPackage::backends() const {
     std::unordered_set<cv::gapi::GBackend> unique_set;
     for (const auto &nn : networks) unique_set.insert(nn.backend);