feat: Added text detection route to API template

[fg-mindee]

As per #233, this PR introduces the following modifications:

• added text detection route to the API template
• added corresponding API unittests

For the following image:

with this piece of code:

import requests
import io
with open('/home/fg/Downloads/detection_sample.jpg', 'rb') as f:
    data = f.read()
response = requests.post("http://localhost:8050/detection", files={'file': io.BytesIO(data)})

which yields

In [4]: response.json()
Out[4]: 
[{'box': [0.826171875, 0.185546875, 0.90234375, 0.201171875]},
 {'box': [0.75390625, 0.185546875, 0.8173828125, 0.201171875]}]

(IoU > 85% with the GT)

Any feedback is welcome!

[codecov]

Codecov Report

Merging #245 (bd3b874) into main (fb24851) will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #245      +/-   ##
==========================================
+ Coverage   97.52%   97.57%   +0.05%     
==========================================
  Files          44       44              
  Lines        1896     1896              
==========================================
+ Hits         1849     1850       +1     
+ Misses         47       46       -1     

Flag	Coverage Δ
unittests	97.57% <ø> (+0.05%)	⬆️

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

Impacted Files	Coverage Δ
doctr/models/detection/linknet.py	98.37% <0.00%> (+0.81%)	⬆️

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[charlesmindee]

Thanks for this feature!