kubectl-auth: add page

[esteramine]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[CLAassistant]

All committers have signed the CLA.

[MachiavelliII]

Thanks for your contribution, and welcome to tldr.

[Managor]

Suggested change

	`kubectl auth can-i '*' '*' -n {{namespace}}`
	- Check if the current user can perform a specific verb on a specific resource:
	`kubectl auth can-i {{verb}} {{resource}} -n {{namespace}}`
	- Check if a specific user or service account can perform an action on a resource:
	`kubectl auth can-i {{verb}} {{resource}} -n {{namespace}} --as {{user_or_sa}}`
	- List all actions the current user is allowed to perform in a namespace:
	`kubectl auth can-i --list -n {{namespace}}`
	`kubectl auth can-i '*' '*' {{[-n|--namespace]}} {{namespace}}`
	- Check if the current user can perform a specific verb on a specific resource:
	`kubectl auth can-i {{verb}} {{resource}} {{[-n|--namespace]}} {{namespace}}`
	- Check if a specific user or service account can perform an action on a resource:
	`kubectl auth can-i {{verb}} {{resource}} {{[-n|--namespace]}} {{namespace}} --as {{user_or_sa}}`
	- List all actions the current user is allowed to perform in a namespace:
	`kubectl auth can-i --list {{[-n|--namespace]}} {{namespace}}`

Either use long options by themselves or use option placeholders like this.