[BFT] Add Staking Key PoP to bootstrapping tools

[tarakby]

Addresses https://github.com/dapperlabs/flow-go/issues/6286

PoP refers to the Proof of Possession of the staking private key. Requiring a PoP is necessary to secure BLS aggregation and SPoCK in the protocol.

This PR includes PoP generation/validation in the bootstrapping command tool:

• Key generation command now generates and outputs the PoP.
• The PoP is part of the public node info, it is written in the public info files when bootstrapping the network data.
• Validation of staking public key now includes staking PoP validation.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 14.96599% with 125 lines in your changes are missing coverage. Please review.

Project coverage is 55.59%. Comparing base (957437f) to head (3cf9e32).
Report is 30 commits behind head on master.

Files	Patch %	Lines
cmd/bootstrap/cmd/final_list.go	0.00%	32 Missing ⚠️
utils/unittest/fixtures.go	0.00%	28 Missing ⚠️
model/bootstrap/node_info.go	26.47%	24 Missing and 1 partial ⚠️
cmd/bootstrap/cmd/keygen.go	0.00%	10 Missing ⚠️
integration/testnet/container.go	0.00%	5 Missing ⚠️
integration/testnet/network.go	16.66%	4 Missing and 1 partial ⚠️
cmd/bootstrap/cmd/partner_infos.go	0.00%	4 Missing ⚠️
cmd/bootstrap/utils/node_info.go	0.00%	4 Missing ⚠️
integration/testnet/util.go	0.00%	3 Missing ⚠️
cmd/bootstrap/cmd/key.go	50.00%	1 Missing and 1 partial ⚠️
... and 4 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2803      +/-   ##
==========================================
+ Coverage   55.49%   55.59%   +0.09%     
==========================================
  Files        1133     1134       +1     
  Lines       89496    89711     +215     
==========================================
+ Hits        49662    49871     +209     
+ Misses      35062    35044      -18     
- Partials     4772     4796      +24     

Flag	Coverage Δ
unittests	55.59% <14.96%> (+0.09%)	⬆️

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