Feature Request: add new commands: configureArguments and buildArguments

[GongT]

This is like the exsists feature in launch.json (document here), but in tasks.json instead.

Configure setting can be more flexible with this two new commands.

for example:

// tasks.json: .tasks[]:
{
	  "label": "configure current target",
	  "type": "shell",
	  "command": "cmake",
	  "args": [
		  "${command:cmake.configureArguments}", // <<===
		  "-DXXX=${input:XXX}"
	  ],
	  "group": "build",
	  "presentation": {
		  "echo": false,
		  "reveal": "always",
		  "focus": true,
		  "panel": "shared",
		  "showReuseMessage": false,
		  "clear": true
	  },
	  "problemMatcher": "$gcc"
},

[elahehrashedi]

this seems to be related to an already requested feature in #2452. I will add this request to that thread so that we can implement them at the same time.