[Client] Add a `Send` or `Broadcast` msg type to the debug CLI

[Olshansk]

Objective

Update the debug CLI to make it clear which debug commands are broadcasts and which are sends.

Origin Document

There was a "fly by" change made in #285 where we updated the strings in app/client/cli/debug.go to the available debug commands by adding broadcast and send to the end like so:

	PromptResetToGenesis         string = "ResetToGenesis (broadcast)"
	PromptPrintNodeState         string = "PrintNodeState (broadcast)"
	PromptTriggerNextView        string = "TriggerNextView (broadcast)"
	PromptTogglePacemakerMode    string = "TogglePacemakerMode (broadcast)"
	PromptShowLatestBlockInStore string = "ShowLatestBlockInStore (send)"

#285 (comment)

The best approach to doing something like this is to update

message DebugMessage {
  DebugMessageAction action = 1;
  google.protobuf.Any message = 2;
}

To:

enum DebugMessageType {
	DEBUG_MESSAGE_TYPE_UNKNOWN = 0;

	DEBUG_MESSAGE_TYPE_SEND = 1;
	DEBUG_MESSAGE_TYPE_BROADCAST = 2;
}

message DebugMessage {
  DebugMessageAction action = 1;
  DebugMessageType type = 2;
  google.protobuf.Any message = 3;
}

Goals

• Make it clear (to the user) which command is a send or broadcast

Deliverable

• Create a SEND and BROADCAST enum type for the debug cmdline
• Update the strings presented to the user to reflect each message type
• Update all downstream business logic to reflect the message type

Non-goals / Non-deliverables

• Adding new debug commands
• Updating send to be able to specify which specific node the command is sent to

General issue deliverables

• Update the appropriate CHANGELOG
• Update any relevant READMEs (local and/or global)
• Update any relevant global documentation & references

Testing Methodology

• All tests: make test_all
• LocalNet: verify a LocalNet is still functioning correctly by following the instructions at docs/development/README.md

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Creator: @Olshansk