Update kctrl usage docs to use a different namespace and not the default one

[praveenrewar]

Describe the problem/challenge you have
From the docs Consuming Packages using CLI, when I copy the command to install the TCE repository and run it, I get an error saying Error: Creating sensitive resources in a shared namespace (default) which is expected but probably not a good experience for someone who is trying it out for the first time.

Describe the solution you'd like
The example usage should use the -n flag to specify a namespace to adhere to the new behaviour of kctrl.

Anything else you would like to add
The same should be done for other examples as well.

[a-mccarthy]

@praveenrewar is this issue still relevant? Is this problem related to TCE specifically or more how the code sample is written? I'd be interested to know how removing TCE references from this page would impact the code references.

[praveenrewar]

@a-mccarthy This issue is not relevant to TCE.
@microwavables brought this up a couple of days back. I will be making some changes to this page to remove TCE references. We could just use some other package repository and that should be fine, but I want to ensure that we can use that same package repository for the end to end workflow described in this page. So I am planning to create a test package repository and use that here.

[a-mccarthy]

Thanks @praveenrewar! Is there a documentation label we can add to this issue?

[praveenrewar]

@a-mccarthy Done!

[praveenrewar]

This was fixed as part of #750