Consider fail fast in CLI commands

[manne]

in many commands the options are checked after connecting to Azure/Azure DevOps. If the check fails both connections were being made unnecessarily. It is beneficial to check them before accessing a different system.

[manne]

Example

aggregator-cli/src/aggregator-cli/Mappings/MapRuleCommand.cs

Lines 29 to 39 in 3916231

	var context = await Context
	.WithAzureLogon()
	.WithDevOpsLogon()
	.Build();
	var mappings = new AggregatorMappings(context.Devops, context.Azure, context.Logger);
	bool ok = DevOpsEvents.IsValidEvent(Event);
	if (!ok)
	{
	context.Logger.WriteError($"Invalid event type.");
	return 2;
	}

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[giuliov]

Partially implemented in v0.9.8.