Implement profiling page for Panel

[philippjfr]

Adds an optional /admin endpoint to Panel with profiling output. This will expand to a number of visualization and views to monitor a live Panel server, including seeing currently active sessions, logging output, callbacks, and much more.

[codecov]

Codecov Report

Merging #2645 (cb96699) into master (5f7e7c0) will decrease coverage by 0.16%.
The diff coverage is 7.40%.

❗ Current head cb96699 differs from pull request most recent head 8145b50. Consider uploading reports for the commit 8145b50 to get more accurate results

@@            Coverage Diff             @@
##           master    #2645      +/-   ##
==========================================
- Coverage   83.00%   82.84%   -0.17%     
==========================================
  Files         184      185       +1     
  Lines       23354    23404      +50     
==========================================
+ Hits        19386    19389       +3     
- Misses       3968     4015      +47     

Impacted Files	Coverage Δ
panel/io/admin.py	0.00% <0.00%> (ø)
panel/io/server.py	58.67% <0.00%> (-0.82%)	⬇️
panel/command/serve.py	14.76% <11.11%> (-0.81%)	⬇️
panel/config.py	58.30% <100.00%> (+0.14%)	⬆️
panel/widgets/indicators.py	92.59% <0.00%> (+0.62%)	⬆️

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[MarcSkovMadsen]

Do I see the terminal in action?

[MarcSkovMadsen]

For inspiration check also scalene out @philippjfr . https://github.com/plasma-umass/scalene

[philippjfr]

@MarcSkovMadsen scalene indeed looks great but I see no way to actually run it from within an existing Python session. The only way I found to invoke it required forking the process and running a code snippet in the forked process.

[MarcSkovMadsen]

For me the main take away is also the look and frem which looks great.