Refactor image inputs and update to new input object

[ethanwharris]

What does this PR do?

Part of #961

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[codecov]

Codecov Report

Merging #997 (cd66eb5) into master (ce18c08) will decrease coverage by 3.43%.
The diff coverage is 91.14%.

@@            Coverage Diff             @@
##           master     #997      +/-   ##
==========================================
- Coverage   88.40%   84.96%   -3.44%     
==========================================
  Files         250      254       +4     
  Lines       13199    13498     +299     
==========================================
- Hits        11668    11469     -199     
- Misses       1531     2029     +498     

Flag	Coverage Δ
unittests	84.96% <91.14%> (-3.44%)	⬇️

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

Impacted Files	Coverage Δ
flash/image/classification/cli.py	84.61% <ø> (ø)
...ash/image/classification/integrations/baal/data.py	41.48% <0.00%> (ø)
flash/image/style_transfer/cli.py	100.00% <ø> (ø)
flash/text/classification/data.py	55.67% <25.00%> (-41.23%)	⬇️
flash/core/data/io/input_base.py	86.45% <28.57%> (-9.93%)	⬇️
flash/core/data/io/input.py	69.70% <50.00%> (-24.80%)	⬇️
flash/image/style_transfer/data.py	91.07% <83.33%> (+1.98%)	⬆️
flash/core/data/utilities/data_frame.py	83.87% <83.87%> (ø)
flash/image/face_detection/data.py	51.56% <84.61%> (+7.90%)	⬆️
flash/core/data/utilities/paths.py	90.90% <89.65%> (+50.55%)	⬆️
... and 31 more

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[tchaton]

LGTM ! Awesome work !