use clap for handling CLI args

[onur-ozkan]

Currently, the help flag is handled in this way:

komodo-defi-framework/mm2src/mm2_main/src/mm2.rs

Lines 152 to 163 in 35e9239

	fn help() {
	const HELP_MSG: &str = r#"Command-line options.
	The first command-line argument is special and designates the mode.
	help .. Display this message.
	btc2kmd {WIF or BTC} .. Convert a BTC WIF into a KMD WIF.
	events .. Listen to a feed coming from a separate MM daemon and print it to stdout.
	vanity {substring} .. Tries to find an address with the given substring.
	update_config {SRC} {DST} .. Update the configuration of coins from the SRC config and save it to DST file.
	{JSON configuration} .. Run the MarketMaker daemon.
	Some (but not all) of the JSON configuration parameters (* - required):

And the CLI arguments are managed like this:

komodo-defi-framework/mm2src/mm2_main/src/mm2.rs

Lines 246 to 262 in 35e9239

	if first_arg == Some("update_config") {
	match on_update_config(&args_os) {
	Ok(_) => println!("Success"),
	Err(e) => eprintln!("{}", e),
	}
	return;
	}
	if first_arg == Some("--version") || first_arg == Some("-v") || first_arg == Some("version") {
	println!("AtomicDEX API: {version}");
	return;
	}
	if first_arg == Some("--help") || first_arg == Some("-h") || first_arg == Some("help") {
	help();
	return;
	}

Nor approach is sustainable/maintainable and they could get unsynced/outdated easily. Use an appropiete library (like clap with derive support) that handles all these automatically. Providing the autocomplete files could be a nice additional feature as well.

Neither approach is sustainable or maintainable and they can easily become outdated or unsynced. Ideally we should use clap (with derive support to handle them on the type level) to handle these automatically. By using clap we can generate the autocomplete files too.