[refactor] SROIE dataset

[felixdittrich92]

This PR refactors the SROIE implementation and enables also rotated boxes

[codecov]

Codecov Report

Merging #660 (16e40a3) into main (8382896) will increase coverage by 0.06%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #660      +/-   ##
==========================================
+ Coverage   96.28%   96.34%   +0.06%     
==========================================
  Files         117      117              
  Lines        4523     4519       -4     
==========================================
- Hits         4355     4354       -1     
+ Misses        168      165       -3     

Flag	Coverage Δ
unittests	96.34% <100.00%> (+0.06%)	⬆️

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

Impacted Files	Coverage Δ
doctr/datasets/sroie.py	97.14% <100.00%> (+2.27%)	⬆️
doctr/models/builder.py	98.21% <0.00%> (+1.78%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8382896...16e40a3. Read the comment docs.

[fg-mindee]

Thanks for the refactor, I added some comments 👍

[fg-mindee]

Looks good thanks!