Fix chain metadata override issue

[NullIsOne]

What is done

• Added sleep to fix issues with immediate finishing of combine publisher
• Replaced some to any at open class URLChainBuilder
• Added missed public modifiers to init of some open Nodes

How to check

• Check any nodeResultPublisher in example or demo project
• Try override URLChainBuilder.metadataConnectorChain. Now it is available. Before it was fail with errors.
• Try create custom ChainBuilder using VoidIONode or VoidOutputNode

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.17%. Comparing base (92be7d6) to head (06483f7).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #147   +/-   ##
=======================================
  Coverage   92.17%   92.17%           
=======================================
  Files          85       85           
  Lines        1955     1956    +1     
=======================================
+ Hits         1802     1803    +1     
  Misses        153      153           

Flag	Coverage Δ
tests	92.17% <100.00%> (+<0.01%)	⬆️

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