Signature Aggregator Flag Groups

[sukantoraymond]

This PR expanded on #2690.

Signature aggregator is already grouped across all commands that use it. Grouping it in all the commands that use it is as simple as adding

	cmd.SetHelpFunc(flags.WithGroupedHelp([]flags.GroupedFlags{sigAggGroup}))

in the end.

For example:

AVL-7H2W7V:avalanche-cli raymondsukanto$ ./bin/avalanche contract initValidatorManager
Usage:
  avalanche contract initValidatorManager blockchainName [flags]

Flags:
      --cluster string                         operate on the given cluster
      --devnet                                 operate on a devnet network
      --endpoint string                        use the given endpoint for network operations
  -f, --fuji testnet                           operate on fuji (alias to testnet
      --genesis-key                            use genesis allocated key as contract deployer
  -h, --help                                   help for initValidatorManager
      --key string                             CLI stored key to use as contract deployer
  -l, --local                                  operate on a local network
  -m, --mainnet                                operate on mainnet
      --pos-maximum-stake-amount uint          (PoS only) maximum stake amount (default 1000)
      --pos-maximum-stake-multiplier uint8     (PoS only )maximum stake multiplier (default 1)
      --pos-minimum-delegation-fee uint16      (PoS only) minimum delegation fee (default 1)
      --pos-minimum-stake-amount uint          (PoS only) minimum stake amount (default 1)
      --pos-minimum-stake-duration uint        (PoS only) minimum stake duration (in seconds) (default 100)
      --pos-reward-calculator-address string   (PoS only) initialize the ValidatorManager with reward calculator address
      --pos-weight-to-value-factor uint        (PoS only) weight to value factor (default 1)
      --private-key string                     private key to use as contract deployer
      --rpc string                             blockchain rpc endpoint
  -t, --testnet fuji                           operate on testnet (alias to fuji)

Global Flags:
      --config string       config file (default is $HOME/.avalanche-cli/config.json)
      --log-level string    log level for the application (default "ERROR")
      --skip-update-check   skip check for new versions

Signature Aggregator Flags:
  (hidden) Use --show-signature-aggregator-flags to show these options