Docs for backbones

[bamblebam]

What does this PR do?

Fixes #718
Adds a central page which has a table table containing available backbones for all the tasks.

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[bamblebam]

How the page looks.

[codecov]

Codecov Report

Merging #735 (f4b8559) into master (23328bd) will decrease coverage by 3.49%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #735      +/-   ##
==========================================
- Coverage   89.06%   85.57%   -3.50%     
==========================================
  Files         198      198              
  Lines       10681    10681              
==========================================
- Hits         9513     9140     -373     
- Misses       1168     1541     +373     

Flag	Coverage Δ
unittests	85.57% <ø> (-3.50%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
flash/text/question_answering/model.py	29.16% <0.00%> (-61.81%)	⬇️
flash/text/question_answering/data.py	28.29% <0.00%> (-57.88%)	⬇️
flash/text/classification/cli.py	57.14% <0.00%> (-42.86%)	⬇️
flash/text/question_answering/cli.py	58.33% <0.00%> (-41.67%)	⬇️
flash/text/seq2seq/core/utils.py	70.00% <0.00%> (-30.00%)	⬇️
flash/text/classification/data.py	62.92% <0.00%> (-28.09%)	⬇️
flash/text/seq2seq/core/metrics.py	74.07% <0.00%> (-25.00%)	⬇️
flash/text/seq2seq/core/data.py	65.85% <0.00%> (-24.40%)	⬇️
flash/text/classification/model.py	70.68% <0.00%> (-22.42%)	⬇️
flash/text/question_answering/finetuning.py	5.49% <0.00%> (-14.29%)	⬇️
... and 7 more

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[ethanwharris]

Hey @bamblebam thanks for your work on this 😃 Since our available backbones change quite a lot and depend on which dependencies you have installed, I think it might be better here to just document how to use the available_backbones and available_heads methods. E.g. you could have an example of available_backbones for the image classifier then available_heads, available_backbones(head) for the ObjectDetector. What do you think?

[bamblebam]

Yeah sounds good I will get that done.

[bamblebam]

I added docs for the available backbones part but when I run print(ObjectDetector.available_heads()) it returns an empty list. Is this intended behaviour?
Also TextClassifier.available_backbones() returns an empty list as well. Is this also intended?

[ethanwharris]

Hi @bamblebam that would be expected for those tasks since they don't have configurable heads. You should get something if you use available_heads with either SemanticSegmentation or ObjectDetector.

Thanks 😃

[bamblebam]

@ethanwharris I checked for available heads but ObjectDetector.available_heads() still returns an empty list. Though SemanticSegmentation.available_heads() returns a list.
I also did the docs so take a look at that and let me know if something needs to be added.

[bamblebam]

@ethanwharris did you take a look ?

[ethanwharris]

Awesome!!! I left a few comments, you will also need to add it at the bottom of index.rst I think. Thanks 😃

[bamblebam]

I updated the index.rst file. I am also marking this as ready for review if there is anything else you want me to do let me know.

[ethanwharris]

Awesome! LGTM 😃