Change classic caffe models related tests and samples to onnx format

[WanliZhong]

Merge with: opencv/opencv_extra#1175
Part of #25314

This PR aims to change the tests and samples related to alexnet, densenet, googlenet, squeezenet, resnet-50 models from caffe framework to onnx. Tests in test_int8_layer.cpp and test_caffe_importer.cpp will be removed in #25323

NOTE:

• Removing the VGG sample in HTML because the model is too large to load in the browser. It's meaningless to add this.
  Error: RuntimeError: Out of bounds memory
• SqueezeNet onnx from opencv_extra is V1 not V1.1, so I change the testname from V1_1to V1
• May conflict with Improved classification sample #25519

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

[WanliZhong]

If I missed some models. Please remind me.

[WanliZhong]

This change is introduced from 4.x in https://github.com/opencv/opencv/pull/25435/files#diff-0f1c399b5f2a43b1c9501dd5fc4d97ae8306099eda327d3096cd84f5b22f2e9f