Improve elastic adapter exception handling

[JSCU-CNI]

This PR improves exception handling of the Elastic adapter. Currently when an Elasticsearch endpoint is unreachable rdump will stay stuck in a thread. We have added a threading.excepthook to make sure rdump exists with a non-zero status code. Let us know if you prefer a different method of propagating exceptions in rdump. Currently the stdout is a bit noisey, but at least rdump is no longer stuck.

Steps to reproduce:

rdump foo.rec -w elastic+https://invalid-hostname?index=foo

[codecov]

Codecov Report

Attention: Patch coverage is 72.22222% with 5 lines in your changes missing coverage. Please review.

Project coverage is 83.87%. Comparing base (941f2cb) to head (c121a97).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
flow/record/adapter/elastic.py	66.66%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #150      +/-   ##
==========================================
- Coverage   83.95%   83.87%   -0.09%     
==========================================
  Files          34       34              
  Lines        3466     3478      +12     
==========================================
+ Hits         2910     2917       +7     
- Misses        556      561       +5     

Flag	Coverage Δ
unittests	83.87% <72.22%> (-0.09%)	⬇️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.