Add GenericLoginHandler for custom OAuth

[philippjfr]

No description provided.

[codecov]

Codecov Report

Merging #2873 (e9d9e89) into master (abea3b0) will increase coverage by 0.00%.
The diff coverage is 71.42%.

❗ Current head e9d9e89 differs from pull request most recent head 58c81e7. Consider uploading reports for the commit 58c81e7 to get more accurate results

@@           Coverage Diff           @@
##           master    #2873   +/-   ##
=======================================
  Coverage   83.04%   83.04%           
=======================================
  Files         188      188           
  Lines       24460    24474   +14     
=======================================
+ Hits        20313    20325   +12     
- Misses       4147     4149    +2     

Impacted Files	Coverage Δ
panel/auth.py	40.46% <71.42%> (+1.30%)	⬆️
panel/io/reload.py	71.11% <0.00%> (+2.22%)	⬆️

---

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 abea3b0...58c81e7. Read the comment docs.

[chenbr]

woot!