Improvements to signal handling

[fridrik01]

This PR makes the following improvements to signal handling, where during graceful shutdown we now:

• only stops services which we called Start() on.
• fixes critical section issue where we can call StopAll twice during shutdown if signal was received while in the middle of Startup.
• only call StopAll during signal handling as that is the only way to stop the service
• simplifies the signal handling to use a simple blocking channel
• call panic if we can't shutdown within receiving 10x SIGTERM signals.

[codecov]

Codecov Report

Attention: Patch coverage is 20.51282% with 31 lines in your changes missing coverage. Please review.

Project coverage is 31.60%. Comparing base (6581265) to head (9cdd7ab).

Files with missing lines	Patch %	Lines
node-core/node/node.go	0.00%	22 Missing ⚠️
node-core/services/registry/registry.go	47.05%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2379      +/-   ##
==========================================
+ Coverage   31.57%   31.60%   +0.03%     
==========================================
  Files         348      348              
  Lines       15530    15527       -3     
  Branches       20       20              
==========================================
+ Hits         4903     4907       +4     
+ Misses      10283    10276       -7     
  Partials      344      344              

Files with missing lines	Coverage Δ
node-core/services/registry/registry.go	48.71% <47.05%> (-2.03%)	⬇️
node-core/node/node.go	0.00% <0.00%> (ø)