Merge pull request #12990 from rgarnov:gapi_fluid_reshape_support

G-API: Introduce new `reshape()` API (#12990)

* Moved initFluidUnits, initLineConsumption, calcLatency, calcSkew to separate functions

* Added Fluid::View::allocate method (moved allocation logic from constructor)

* Changed util::zip to util::indexed, utilized collectInputMeta in GFluidExecutable constructor

* Added makeReshape method to FluidExecutable

* Removed m_outputRoi from GFluidExecutable

* Added reshape feature

* Added switch of resize mapper if agent ratio was changed

* Added more TODOs and renamed a function

* G-API reshape(): add missing `override` specifiers

Fix warnings on all platforms

modules/gapi/src/executor/gexecutor.hpp

@@ -85,6 +85,9 @@ public:
     explicit GExecutor(std::unique_ptr<ade::Graph> &&g_model);
     void run(cv::gimpl::GRuntimeArgs &&args);
 
+    bool canReshape() const;
+    void reshape(const GMetaArgs& inMetas, const GCompileArgs& args);
+
     const GModel::Graph& model() const; // FIXME: make it ConstGraph?
 };