docs: Add README for using 4 types of OAuth apps

[chyroc]

• Documented usage instructions for 4 types of OAuth apps
• Included WebOAuthApp, JWTOAuthApp, PKCEOAuthApp and DeviceOAuthApp

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.86%. Comparing base (838cc70) to head (c32852c).
Report is 6 commits behind head on main.

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  Coverage   71.86%   71.86%           
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  Files          30       30           
  Lines        1134     1134           
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  Hits          815      815           
  Misses        319      319           

Flag	Coverage Δ
	71.86% <ø> (ø)

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