Add support for downloading DNN config files in download_models.py #26186
PR resloves #26160 related to downloading DNN config files using download_models.py
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] 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
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
Improved and refactored text detection sample in dnn module #25326
Clean up samples: #25006
This pull requests merges and simplifies different text detection samples in dnn module of opencv in to one file. An option has been provided to choose the detection model from EAST or DB
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] 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
- [x] The PR is proposed to the proper branch
- [x] 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.
- [x] The feature is well documented and sample code can be built with the project CMake
Scripts for downloading models in DNN samples
* Initial commit. Utility classes and functions for downloading files
* updated download script
* Support YAML parsing, update download script and configs
* Fix problem with archived files
* fix models.yml
* Move download utilities to more appropriate place
* Fix script description
* Update README
* update utilities for broader range of files
* fix loading with no hashsum provided
* remove unnecessary import
* fix for Python2
* Add usage examples for downloadFile function
* Add more secure cache folder selection
* Remove trailing whitespaces
* Fix indentation
* Update function interface
* Change function for temp dir, change entry name in models.yml
* Update getCacheDirectory function call
* Return python implementation for cache directory selection, use more specific env variable
* Fix whitespace
