Allow many_buttons to be run without text

[ickshonpe]

Objective

many_buttons isn't a good benchmark in all cases because it draws so much text. Allow many_buttons to be run without text.

Solution

If the command-line flag no-text is specified, don't draw any text.

Changelog

• many_buttons can now be run without text. To start without text run: cargo run --example many_buttons --release no-text

[mockersf]

Rather than rely on features, several other many_* examples accept command line parameters to change their behaviour.

Very simple flag like in

bevy/examples/stress_tests/many_cubes.rs

Lines 52 to 53 in 52b91ac

	match std::env::args().nth(1).as_deref() {
	Some("sphere") => {

[ickshonpe]

I see, yes that's much simpler with commandline params. Changed it.