Support multiple groups and pipelines

[lquerel]

Closes #1812

This PR adds support for multiple pipeline groups and multiple pipelines per group. It is still possible to start the engine with a single pipeline, but it is now also possible to start the engine with a configuration file describing one or more pipeline groups. An example configuration is included in this PR.

The controller documentation has been updated to provide more details. Optimal placement of the ITS and pipelines per NUMA node is not yet implemented. Named channels are not implemented yet.

I did not observe any performance regression with this PR.

[codecov]

Codecov Report

❌ Patch coverage is 18.59649% with 232 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.62%. Comparing base (d8a0d6d) to head (e97c423).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1823      +/-   ##
==========================================
- Coverage   84.70%   84.62%   -0.08%     
==========================================
  Files         498      498              
  Lines      146255   146385     +130     
==========================================
- Hits       123879   123875       -4     
- Misses      21842    21976     +134     
  Partials      534      534              

Components	Coverage Δ
otap-dataflow	86.01% <18.59%> (-0.13%)	⬇️
query_abstraction	80.61% <ø> (ø)
query_engine	90.52% <ø> (ø)
syslog_cef_receivers	∅ <ø> (∅)
otel-arrow-go	53.50% <ø> (ø)
quiver	90.66% <ø> (ø)

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