Add examples with basic config

[Wiktor-99]

I struggle to get these configs working for me, so I think it might be helpful to add such examples.

[nuclearsandwich]

I could see some utility in --mixin verbose to manage the console_direct event handler but I don't think there's any advantage to creating a mixin for the merge-install flag.

[nuclearsandwich]

Can you explain how you use this?

Without the mixin, an invocation would use

colcon build --merge-instal ...

But with the mixin it would be

colcon build --mixin merge-install

to do the exact same thing so I don't think this mixin makes sense.

[Wiktor-99]

When you put it this way, it does seem odd. My use case includes other things, like many cmake arguments and so on. I've struggled to add this as an additional option, so I wanted to leave it here as an example.