feat(gnodev): add /reload and /reset endpoints

[n0izn0iz]

This exposes the Reload and Reset methods via http in gnodev
It allows to run UI E2E tests automatically without having to restart gnodev between each tests and thus makes usage in Cypress very easy

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 15 lines in your changes missing coverage. Please review.

Project coverage is 54.69%. Comparing base (1c162de) to head (aa1167b).

Files	Patch %	Lines
contribs/gnodev/cmd/gnodev/main.go	0.00%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2448      +/-   ##
==========================================
- Coverage   54.70%   54.69%   -0.02%     
==========================================
  Files         590      590              
  Lines       79036    79051      +15     
==========================================
  Hits        43236    43236              
- Misses      32550    32565      +15     
  Partials     3250     3250              

Flag	Coverage Δ
contribs/gnodev	23.53% <0.00%> (-0.28%)	⬇️
contribs/gnofaucet	14.46% <ø> (ø)
contribs/gnokeykc	0.00% <ø> (ø)
contribs/gnomd	0.00% <ø> (ø)

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[gfanton]

Thank you for this contribution. I really like the idea of controlling Gnodev from the outside !
We can start with this simple API, but we may create a dedicated package for it if the API expands.