Move TF OD API docs to code + several fixes for TF OD API models conversion

[lazarevevgeny]

Root cause analysis: The documentation and code comments related to the conversion of the TF OD API models is not up to date.

Solution:

1. Merge most part of the documentation into the MO code. Removed a lot of out of date documentation sections.
2. Updated node names to properly match content they produce.
3. Removed old workaround to update the infer function of the DetectionOutput operation in the ObjectDetectionAPISSDPostprocessorReplacement. Implemented the same functionality with a sub-graph of nodes.
4. Fixed MO transformation which removes the pre-processing block to properly work in case when the input image is scaled and mean value subtracted first, then resized and finally padded. In this case the scale/mean operations are removed as well.
5. Fixed shape calculation function which produces output shape for case when "pad_to_max_dimension" is used. The padding is not counted anymore since this is not a true part of the pre-processing and is handled separately.
6. Updated a lot of comments produced by MO when removing the pre-processing block.
7. Fixed typo in the unit test for the PipelineConfig parser which results in parsing only part of the input file.
8. Get rid of "coordinates_swap_method" parameter from the JSON config used to insert DetectionOutput operation. Now this information is obtained directly from the model.

Ticket: 51541, 24709

Additional e2e validation performed:

• All TF 1.X OD API models of version 1.15.2 + RFCN 1.9 version of the model
• All TF 1.X OD API models of version 1.15.2 with mode when second DetectionOutput is inserted instead of Proposal (to make sure that another branch of the Proposal op replacement works correctly)
• TF 2.X OD API models which passed successfully with master branch
• Validated with the models from tickets: 62407, 49852

Code:

• Comments
• Code style (PEP8)
• Transformation generates reshape-able IR: no significant changes with respect to this feature
• Transformation preserves original framework node names: no significant changes with respect to this feature

Validation:

• Unit tests: Done
• Framework operation tests: N/A no new op enabled
• Transformation tests: updated some existing tests. Verified with testing of many TF OD API models e2e testing
• Model Optimizer IR Reader check

Documentation:

• Supported frameworks operations list: N/A no new ops enabled
• Guide on how to convert the public model: Done
• User guide update: Done

TODO:

• Simplify code related to swapping XY->YX coordinates.