Pass count to the command called by remapper

Is your feature request related to a problem? Please describe.
This is to solve https://github.com/VSpaceCode/VSpaceCode/issues/278.

When a user used vim.normalModeKeyBindingsNonRecursive to remap to a command,

1. there's no way for an extension to integrate with the count information
2. The count still persist after the command executed

For example:

"vim.normalModeKeyBindingsNonRecursive": [
	{
		"before": ["<space>"],
		"commands": ["vspacecode.space"],
	},
]

VSpaceCode has no way to get the count when a user press 2 <space>, and after the command has been executed the 2 still exists.

Describe the solution you'd like
Is there any way we can pass the count (or more general the vim state) when we call the command?

For example:

"vim.normalModeKeyBindingsNonRecursive": [
	{
		"before": ["<space>"],
		"commands": [
			{"command": "whichkey.triggerKey", args: "$count"}
		],
	},
]

The remapper will inspect the args and replace $count with the count. This can also support other variables like $registers.

Describe alternatives you've considered

"vim.normalModeKeyBindingsNonRecursive": [
	{
		"before": ["<space>"],
		"commands": [
			{"commandWithVimState": "whichkey.triggerKey"}
		],
	},
]

When space is entered, it will pass vim state as parameter when executing command the vscode.commands.executeCommand(commandString, vimState).

Start by tracing how the remapper executes commands from normalModeKeyBindingsNonRecursive and how count state is retained after execution. Compare the proposed args substitution with passing the full Vim state, then verify that a remapped command can receive the count and that the count no longer persists.