* Create text_detection.py

#12270 #13429
**Deep Learning text detection sample (Python)**
- Tested on **Ubuntu 18.04** - OpenCV 3.4.3, OpenCV 3.4.4, OpenCV 4.0 (master branch)
- Python version supported - Python 2 and Python 3

* Fix trailing whitespaces

* Update text_detection.py

* Remove whitespace

* Remove comments

* Remove unused packages

* Update description