Expose node component management

[janezpodhostnik]

I wanted to use the framework for composing a node that we have in the gateway without duplicating a lot of the code onflow/flow-evm-gateway#682

The changes I needed were:

• FlowNodeImp has *NodeConfig which I did not want to use so I pulled out a sub component NodeImp that does not have that. This forced me to change some log lines. All the info is still there, but it is in the fields instead of the message.
• moving the ctx, cancel := context.WithCancel(context.Background()) from Run to run is not strictly necessary, but it was a bit confusing so I refactored it (I can potentially put this in a separate PR)
• Next thing I needed was the handleComponent from FlowNodeBuilder so I changed it into a function that accepts components and a component builder + the input AddWorkersFromComponents. On Flow nodes the input is *NodeConfig, but with making ReadyDoneFactory generic the input can be anything.
• Last change is strictly not related, and I can put it in a separate PR: I changed the metrics server into a component so that the context can be injected at the start of the metrics server.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 62.03704% with 41 lines in your changes missing coverage. Please review.

Project coverage is 41.23%. Comparing base (8a3055c) to head (bacae24).

Files with missing lines	Patch %	Lines
module/metrics/server.go	0.00%	38 Missing ⚠️
cmd/scaffold.go	95.34%	2 Missing ⚠️
cmd/node_builder.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6769      +/-   ##
==========================================
- Coverage   41.26%   41.23%   -0.03%     
==========================================
  Files        2061     2061              
  Lines      182702   182736      +34     
==========================================
- Hits        75384    75355      -29     
- Misses     101010   101075      +65     
+ Partials     6308     6306       -2     

Flag	Coverage Δ
unittests	41.23% <62.03%> (-0.03%)	⬇️

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