feat(cmd): pass Start options; add WithFlagSet option

[tuxcanfly]

Fixes #2936

This PR updates the Start command to accept a variadic number of funcs which can be used to customise the command.

This allows the caller to hook into and modify the command, for example to add a PreRun hook, as required for celestia-da.

With this PR in place, the celestia-da requirement, which needs to add some required flags and add a PreRun hook can be satisfied as:

	bridgeCmd := bridge.NewCommand(WithPreRun())
	lightCmd := light.NewCommand(WithPreRun())
	fullCmd := full.NewCommand(WithPreRun())

Ideally this can be applied for other commands Init, Auth as well, but it's not required for the current requirement.

[codecov-commenter]

Codecov Report

Attention: 73 lines in your changes are missing coverage. Please review.

Comparison is base (d1883d6) 51.43% compared to head (4a2e37e) 50.87%.

Files	Patch %	Lines
cmd/node.go	0.00%	65 Missing ⚠️
cmd/util.go	0.00%	5 Missing ⚠️
cmd/start.go	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2950      +/-   ##
==========================================
- Coverage   51.43%   50.87%   -0.56%     
==========================================
  Files         170      168       -2     
  Lines       10925    10937      +12     
==========================================
- Hits         5619     5564      -55     
- Misses       4807     4873      +66     
- Partials      499      500       +1     

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[ramin]

personally would like to give this another refactor, which might be out of scope for this PR, unless this refactoring creates an external contract with what you are doing in celestia-da? Otherwise, this is a good first step to making it a bit nicer to work with, even if some of the indirection of what gets passed in and around is too clever for me, i think fix some of the ordering nits i made, and clarify if passing bridge.WithSubCommands is correct or not and lets roll

[Wondertan]

LGTM