Security BCP: Remove OOB

[n2ygk]

Fixes #1104

Description of the Change

Remove support for insecure urn:ietf:wg:oauth:2.0:oob and urn:ietf:wg:oauth:2.0:oob:auto which are replaced
by RFC 8252 "OAuth 2.0 for Native Apps" BCP. Google has deprecated use of oob with a final end date of 2022-10-03.

Checklist

• PR only contains one change (considered splitting up PR)
• unit-test added removed
• documentation updated (oob support was never documented)
• CHANGELOG.md updated (only for user relevant changes)
• author name in AUTHORS

[codecov]

Codecov Report

Merging #1124 (b5188ee) into master (e761ebc) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1124      +/-   ##
==========================================
- Coverage   96.62%   96.59%   -0.03%     
==========================================
  Files          32       32              
  Lines        1806     1794      -12     
==========================================
- Hits         1745     1733      -12     
  Misses         61       61              

Impacted Files	Coverage Δ
oauth2_provider/views/base.py	97.58% <100.00%> (-0.22%)	⬇️

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